From fa4711ff7b39a3df798f551317c0e3ca0f2da703 Mon Sep 17 00:00:00 2001
From: "Calum H." <calum@modrinth.com>
Date: Wed, 1 Apr 2026 19:53:19 +0200
Subject: [PATCH] feat: implement improved flow for server panel edit
 installation (#5711)

* feat: implement improved flow for server panel edit installation

* feat: installation form finalized

* feat: error state for InstallingBanner

* feat: action button refactor + save banner text fix

* fix: lint

* fix: content card alignment

* feat: better copy

* fix: lint

* fix: hide shift click + fix NeoForge chip

* fix: lint
---
 .../ui/servers/PanelServerActionButton.vue    | 166 +++++++--------
 .../src/components/ui/servers/SaveBanner.vue  |  24 ++-
 .../src/pages/hosting/manage/[id].vue         |  73 ++-----
 .../hosting/manage/[id]/options/loader.vue    |  75 ++++++-
 .../api-client/src/modules/archon/types.ts    |   6 +
 .../components/ModpackStage.vue               |   1 +
 .../creation-flow-context.ts                  |  11 +
 .../components/servers/InstallingBanner.vue   |  63 +++++-
 .../components/ContentModpackCard.vue         |   2 +-
 .../modals/ConfirmBulkUpdateModal.vue         |   6 +
 .../components/modals/InlineBackupCreator.vue |   3 +-
 .../components/ContentDiffModal.vue           |   1 +
 .../components/IncompatibleContentModal.vue   | 194 ++++++++++++++++++
 .../composables/index.ts                      |   2 +-
 .../composables/use-installation-form.ts      | 134 ++++++++++++
 .../shared/installation-settings/layout.vue   |  36 +++-
 .../providers/installation-settings.ts        |  21 ++
 packages/ui/src/locales/en-US/index.json      |  27 +++
 .../servers/InstallingBanner.stories.ts       | 108 ++++++++++
 19 files changed, 785 insertions(+), 168 deletions(-)
 create mode 100644 packages/ui/src/layouts/shared/installation-settings/components/IncompatibleContentModal.vue
 create mode 100644 packages/ui/src/stories/servers/InstallingBanner.stories.ts

diff --git a/apps/frontend/src/components/ui/servers/PanelServerActionButton.vue b/apps/frontend/src/components/ui/servers/PanelServerActionButton.vue
index 9f2d465ce..3022a7b06 100644
--- a/apps/frontend/src/components/ui/servers/PanelServerActionButton.vue
+++ b/apps/frontend/src/components/ui/servers/PanelServerActionButton.vue
@@ -4,19 +4,19 @@
 			<div class="flex flex-col gap-4 md:w-[400px]">
 				<p class="m-0">
 					Are you sure you want to
-					<span class="lowercase">{{ confirmActionText }}</span> the server?
+					<span class="lowercase">{{ pendingAction }}</span> the server?
 				</p>
 				<Checkbox
 					v-model="dontAskAgain"
 					label="Don't ask me again"
 					class="text-sm"
-					:disabled="!powerAction"
+					:disabled="!pendingAction"
 				/>
 				<div class="flex flex-row gap-4">
 					<ButtonStyled type="standard" color="brand" @click="executePowerAction">
 						<button>
 							<CheckIcon class="h-5 w-5" />
-							{{ confirmActionText }} server
+							{{ pendingAction }} server
 						</button>
 					</ButtonStyled>
 					<ButtonStyled @click="resetPowerAction">
@@ -31,11 +31,11 @@
 
 		<NewModal
 			ref="detailsModal"
-			:header="`All of ${serverName || 'Server'} info`"
-			@close="closeDetailsModal"
+			:header="`All of ${server.name || 'Server'} info`"
+			@close="detailsModal?.hide()"
 		>
 			<ServerInfoLabels
-				:server-data="serverData"
+				:server-data="server"
 				:show-game-label="true"
 				:show-loader-label="true"
 				:uptime-seconds="uptimeSeconds"
@@ -43,9 +43,9 @@
 				class="mb-6 flex flex-col gap-2"
 			/>
 			<div v-if="flags.advancedDebugInfo" class="markdown-body">
-				<pre>{{ serverData }}</pre>
+				<pre>{{ server }}</pre>
 			</div>
-			<ButtonStyled type="standard" color="brand" @click="closeDetailsModal">
+			<ButtonStyled type="standard" color="brand" @click="detailsModal?.hide()">
 				<button class="w-full">Close</button>
 			</ButtonStyled>
 		</NewModal>
@@ -62,14 +62,14 @@
 					<button :disabled="!canTakeAction" @click="initiateAction('Stop')">
 						<div class="flex gap-1">
 							<StopCircleIcon class="h-5 w-5" />
-							<span>{{ isStoppingState ? 'Stopping...' : 'Stop' }}</span>
+							<span>{{ isStopping ? 'Stopping...' : 'Stop' }}</span>
 						</div>
 					</button>
 				</ButtonStyled>
 
 				<ButtonStyled type="standard" color="brand" size="large">
-					<button v-tooltip="busyReason" :disabled="!canTakeAction" @click="handlePrimaryAction">
-						<div v-if="isTransitionState" class="grid place-content-center">
+					<button v-tooltip="busyTooltip" :disabled="!canTakeAction" @click="handlePrimaryAction">
+						<div v-if="isTransitioning" class="grid place-content-center">
 							<LoadingIcon />
 						</div>
 						<component :is="isRunning ? UpdatedIcon : PlayIcon" v-else />
@@ -116,8 +116,16 @@ import {
 	UpdatedIcon,
 	XIcon,
 } from '@modrinth/assets'
-import { ButtonStyled, Checkbox, NewModal, ServerInfoLabels } from '@modrinth/ui'
-import type { PowerAction as ServerPowerAction, ServerState } from '@modrinth/utils'
+import {
+	ButtonStyled,
+	Checkbox,
+	injectModrinthClient,
+	injectModrinthServerContext,
+	injectNotificationManager,
+	NewModal,
+	ServerInfoLabels,
+	useVIntl,
+} from '@modrinth/ui'
 import { useStorage } from '@vueuse/core'
 import { computed, ref } from 'vue'
 import { useRouter } from 'vue-router'
@@ -126,70 +134,60 @@ import LoadingIcon from './icons/LoadingIcon.vue'
 import PanelSpinner from './PanelSpinner.vue'
 import TeleportOverflowMenu from './TeleportOverflowMenu.vue'
 
-const flags = useFeatureFlags()
-
-interface PowerAction {
-	action: ServerPowerAction
-	nextState: ServerState
-}
+type PowerAction = 'Start' | 'Stop' | 'Restart' | 'Kill'
 
 const props = defineProps<{
-	isOnline: boolean
-	isActioning: boolean
-	isInstalling: boolean
-	disabled: boolean
-	serverName?: string
-	serverData: object
+	disabled?: boolean
 	uptimeSeconds: number
-	busyReason?: string
-}>()
-
-const emit = defineEmits<{
-	(e: 'action', action: ServerPowerAction): void
 }>()
 
+const { formatMessage } = useVIntl()
+const flags = useFeatureFlags()
 const router = useRouter()
-const serverId = router.currentRoute.value.params.id
+const client = injectModrinthClient()
+const { serverId, server, powerState, busyReasons } = injectModrinthServerContext()
+const { addNotification } = injectNotificationManager()
+
 const confirmActionModal = ref<InstanceType<typeof NewModal> | null>(null)
 const detailsModal = ref<InstanceType<typeof NewModal> | null>(null)
+const pendingAction = ref<PowerAction | null>(null)
+const dontAskAgain = ref(false)
 
 const userPreferences = useStorage(`pyro-server-${serverId}-preferences`, {
 	powerDontAskAgain: false,
 })
 
-const serverState = ref<ServerState>(props.isOnline ? 'running' : 'stopped')
-const powerAction = ref<PowerAction | null>(null)
-const dontAskAgain = ref(false)
-const startingDelay = ref(false)
+const isInstalling = computed(() => server.value.status === 'installing')
+const isRunning = computed(() => powerState.value === 'running')
+const isStopping = computed(() => powerState.value === 'stopping')
+const isTransitioning = computed(
+	() => powerState.value === 'starting' || powerState.value === 'stopping',
+)
+const showStopButton = computed(() => isRunning.value || isStopping.value)
+
+const busyTooltip = computed(() =>
+	busyReasons.value.length > 0 ? formatMessage(busyReasons.value[0].reason) : undefined,
+)
 
 const canTakeAction = computed(
-	() => !props.isActioning && !startingDelay.value && !isTransitionState.value && !props.busyReason,
+	() => !isTransitioning.value && !props.disabled && busyReasons.value.length === 0,
 )
-const isRunning = computed(() => serverState.value === 'running')
-const isTransitionState = computed(() =>
-	['starting', 'stopping', 'restarting'].includes(serverState.value),
-)
-const isStoppingState = computed(() => serverState.value === 'stopping')
-const showStopButton = computed(() => isRunning.value || isStoppingState.value)
 
 const primaryActionText = computed(() => {
-	const states: Partial<Record<ServerState, string>> = {
-		starting: 'Starting...',
-		restarting: 'Restarting...',
-		running: 'Restart',
-		stopping: 'Stopping...',
-		stopped: 'Start',
+	switch (powerState.value) {
+		case 'starting':
+			return 'Starting...'
+		case 'stopping':
+			return 'Stopping...'
+		case 'running':
+			return 'Restart'
+		default:
+			return 'Start'
 	}
-	return states[serverState.value]
-})
-
-const confirmActionText = computed(() => {
-	if (!powerAction.value) return ''
-	return powerAction.value.action.charAt(0).toUpperCase() + powerAction.value.action.slice(1)
 })
 
 const menuOptions = computed(() => [
-	...(props.isInstalling
+	...(isInstalling.value
 		? []
 		: [
 				{
@@ -221,28 +219,31 @@ const menuOptions = computed(() => [
 ])
 
 async function copyId() {
-	await navigator.clipboard.writeText(serverId as string)
+	await navigator.clipboard.writeText(serverId)
 }
 
-function initiateAction(action: ServerPowerAction) {
+async function sendPowerAction(action: PowerAction) {
+	try {
+		await client.archon.servers_v0.power(serverId, action)
+	} catch (error) {
+		console.error(`Error performing ${action} on server:`, error)
+		addNotification({
+			type: 'error',
+			title: `Failed to ${action.toLowerCase()} server`,
+			text: 'An error occurred while performing this action.',
+		})
+	}
+}
+
+function initiateAction(action: PowerAction) {
 	if (!canTakeAction.value) return
 
-	const stateMap: Record<ServerPowerAction, ServerState> = {
-		Start: 'starting',
-		Stop: 'stopping',
-		Restart: 'restarting',
-		Kill: 'stopping',
-	}
-
 	if (action === 'Start') {
-		emit('action', action)
-		serverState.value = stateMap[action]
-		startingDelay.value = true
-		setTimeout(() => (startingDelay.value = false), 5000)
+		sendPowerAction(action)
 		return
 	}
 
-	powerAction.value = { action, nextState: stateMap[action] }
+	pendingAction.value = action
 
 	if (userPreferences.value.powerDontAskAgain) {
 		executePowerAction()
@@ -256,41 +257,20 @@ function handlePrimaryAction() {
 }
 
 function executePowerAction() {
-	if (!powerAction.value) return
+	if (!pendingAction.value) return
 
-	const { action, nextState } = powerAction.value
-	emit('action', action)
-	serverState.value = nextState
+	sendPowerAction(pendingAction.value)
 
 	if (dontAskAgain.value) {
 		userPreferences.value.powerDontAskAgain = true
 	}
 
-	if (action === 'Start') {
-		startingDelay.value = true
-		setTimeout(() => (startingDelay.value = false), 5000)
-	}
-
 	resetPowerAction()
 }
 
 function resetPowerAction() {
 	confirmActionModal.value?.hide()
-	powerAction.value = null
+	pendingAction.value = null
 	dontAskAgain.value = false
 }
-
-function closeDetailsModal() {
-	detailsModal.value?.hide()
-}
-
-watch(
-	() => props.isOnline,
-	(online) => (serverState.value = online ? 'running' : 'stopped'),
-)
-
-watch(
-	() => router.currentRoute.value.fullPath,
-	() => closeDetailsModal(),
-)
 </script>
diff --git a/apps/frontend/src/components/ui/servers/SaveBanner.vue b/apps/frontend/src/components/ui/servers/SaveBanner.vue
index caf1bd7da..092ca3b60 100644
--- a/apps/frontend/src/components/ui/servers/SaveBanner.vue
+++ b/apps/frontend/src/components/ui/servers/SaveBanner.vue
@@ -18,8 +18,8 @@
 							</button>
 						</ButtonStyled>
 						<ButtonStyled v-if="props.restart" type="standard" color="brand">
-							<button :disabled="props.isUpdating" @click="saveAndRestart">
-								{{ props.isUpdating ? 'Saving...' : 'Save & restart' }}
+							<button :disabled="props.isUpdating || isTransitioning" @click="saveAndPower">
+								{{ powerButtonLabel }}
 							</button>
 						</ButtonStyled>
 					</div>
@@ -30,7 +30,8 @@
 </template>
 
 <script setup lang="ts">
-import { ButtonStyled, injectModrinthClient } from '@modrinth/ui'
+import { ButtonStyled, injectModrinthClient, injectModrinthServerContext } from '@modrinth/ui'
+import { computed } from 'vue'
 
 const props = defineProps<{
 	isUpdating: boolean
@@ -42,10 +43,23 @@ const props = defineProps<{
 }>()
 
 const client = injectModrinthClient()
+const { powerState } = injectModrinthServerContext()
 
-const saveAndRestart = async () => {
+const isStopped = computed(() => powerState.value === 'stopped' || powerState.value === 'crashed')
+
+const isTransitioning = computed(
+	() => powerState.value === 'starting' || powerState.value === 'stopping',
+)
+
+const powerButtonLabel = computed(() => {
+	if (props.isUpdating) return 'Saving...'
+	if (isTransitioning.value) return isStopped.value ? 'Save & start' : 'Save & restart'
+	return isStopped.value ? 'Save & start' : 'Save & restart'
+})
+
+const saveAndPower = async () => {
 	props.save()
-	await client.archon.servers_v0.power(props.serverId, 'Restart')
+	await client.archon.servers_v0.power(props.serverId, isStopped.value ? 'Start' : 'Restart')
 }
 </script>
 
diff --git a/apps/frontend/src/pages/hosting/manage/[id].vue b/apps/frontend/src/pages/hosting/manage/[id].vue
index 9eed7db68..be76662c7 100644
--- a/apps/frontend/src/pages/hosting/manage/[id].vue
+++ b/apps/frontend/src/pages/hosting/manage/[id].vue
@@ -172,17 +172,7 @@
 			</template>
 			<template #actions>
 				<div v-if="isConnected && !serverData.flows?.intro" class="flex gap-2">
-					<PanelServerActionButton
-						:is-online="isServerRunning"
-						:is-actioning="isActioning"
-						:is-installing="serverData.status === 'installing'"
-						:disabled="isActioning || !!error"
-						:server-name="serverData.name"
-						:server-data="serverData"
-						:uptime-seconds="uptimeSeconds"
-						:busy-reason="busyReasons.length > 0 ? formatMessage(busyReasons[0].reason) : undefined"
-						@action="sendPowerAction"
-					/>
+					<PanelServerActionButton :disabled="!!error" :uptime-seconds="uptimeSeconds" />
 				</div>
 			</template>
 		</ContentPageHeader>
@@ -320,12 +310,14 @@
 				>
 					<InstallingBanner
 						v-if="
-							(serverData.status === 'installing' || isSyncingContent) &&
+							(serverData.status === 'installing' || isSyncingContent || contentError) &&
 							syncProgress?.phase !== 'Analyzing'
 						"
 						data-pyro-server-installing
 						class="mb-4"
 						:progress="syncProgress"
+						:content-error="contentError"
+						@retry="handleContentRetry"
 					>
 						<template #icon>
 							<ServerIcon :image="serverImage" class="!h-6 !w-6" />
@@ -398,9 +390,8 @@ import {
 	ServerNotice,
 	ServerOnboardingPanelPage,
 	useDebugLogger,
-	useVIntl,
 } from '@modrinth/ui'
-import type { PowerAction, Stats } from '@modrinth/utils'
+import type { Stats } from '@modrinth/utils'
 import { useQuery, useQueryClient } from '@tanstack/vue-query'
 import { useTimeoutFn } from '@vueuse/core'
 import DOMPurify from 'dompurify'
@@ -416,7 +407,6 @@ import { useServerProject } from '~/composables/servers/use-server-project.ts'
 import { useModrinthServersConsole } from '~/store/console.ts'
 
 const { addNotification } = injectNotificationManager()
-const { formatMessage } = useVIntl()
 const client = injectModrinthClient()
 
 const isReconnecting = ref(false)
@@ -505,7 +495,6 @@ const modrinthServersConsole = useModrinthServersConsole()
 const queryClient = useQueryClient()
 const cpuData = ref<number[]>([])
 const ramData = ref<number[]>([])
-const isActioning = ref(false)
 const isServerRunning = computed(() => serverPowerState.value === 'running')
 const serverPowerState = ref<Archon.Websocket.v0.PowerState>('stopped')
 const powerStateDetails = ref<{ oom_killed?: boolean; exit_code?: number }>()
@@ -518,6 +507,7 @@ const markBackupCancelled = (backupId: string) => {
 
 // Parthenon state event
 const syncProgress = ref<Archon.Websocket.v0.SyncContentProgress | null>(null)
+const contentError = ref<Archon.Websocket.v0.SyncContentError | null>(null)
 const syncProgressActive = ref(false)
 const isAwaitingPostInstallRefresh = ref(false)
 const { start: startSyncHide, stop: cancelSyncHide } = useTimeoutFn(
@@ -845,6 +835,7 @@ const handleState = (data: Archon.Websocket.v0.WSStateEvent) => {
 		serverStatus: serverData.value?.status,
 	})
 	syncProgress.value = data.progress
+	contentError.value = data.content_error
 
 	// Sync power state from the state event
 	const powerMap: Record<Archon.Websocket.v0.FlattenedPowerState, Archon.Websocket.v0.PowerState> =
@@ -878,6 +869,7 @@ const handleState = (data: Archon.Websocket.v0.WSStateEvent) => {
 			hasSeenInstallProgress = true
 		} else if (
 			data.progress == null &&
+			data.content_error == null &&
 			serverData.value.status === 'installing' &&
 			hasSeenInstallProgress
 		) {
@@ -889,6 +881,18 @@ const handleState = (data: Archon.Websocket.v0.WSStateEvent) => {
 	}
 }
 
+async function handleContentRetry() {
+	if (!worldId.value) return
+	try {
+		await client.archon.content_v1.repair(serverId, worldId.value)
+	} catch (err) {
+		addNotification({
+			type: 'error',
+			text: err instanceof Error ? err.message : 'Failed to retry installation',
+		})
+	}
+}
+
 const handleUptime = (data: Archon.Websocket.v0.WSUptimeEvent) => {
 	stopUptimeUpdates()
 	uptimeSeconds.value = data.uptime
@@ -1219,43 +1223,6 @@ const updateGraphData = (dataArray: number[], newValue: number): number[] => {
 	return updated
 }
 
-const toAdverb = (word: string) => {
-	if (word.endsWith('p')) {
-		return word + 'ping'
-	}
-	if (word.endsWith('e')) {
-		return word.slice(0, -1) + 'ing'
-	}
-	if (word.endsWith('ie')) {
-		return word.slice(0, -2) + 'ying'
-	}
-	return word + 'ing'
-}
-
-const sendPowerAction = async (action: PowerAction) => {
-	const actionName = action.charAt(0).toUpperCase() + action.slice(1)
-	try {
-		isActioning.value = true
-		await client.archon.servers_v0.power(serverId, action)
-	} catch (error) {
-		console.error(`Error ${toAdverb(actionName)} server:`, error)
-		notifyError(
-			`Error ${toAdverb(actionName)} server`,
-			'An error occurred while performing this action.',
-		)
-	} finally {
-		isActioning.value = false
-	}
-}
-
-const notifyError = (title: string, text: string) => {
-	addNotification({
-		title,
-		text,
-		type: 'error',
-	})
-}
-
 const nodeUnavailableDetails = computed(() => [
 	{
 		label: 'Server ID',
diff --git a/apps/frontend/src/pages/hosting/manage/[id]/options/loader.vue b/apps/frontend/src/pages/hosting/manage/[id]/options/loader.vue
index e0ddf660b..d68397c2f 100644
--- a/apps/frontend/src/pages/hosting/manage/[id]/options/loader.vue
+++ b/apps/frontend/src/pages/hosting/manage/[id]/options/loader.vue
@@ -8,7 +8,7 @@
 			@proceed="confirmResetToOnboarding"
 		/>
 
-		<InstallationSettingsLayout ref="installationSettingsLayout">
+		<InstallationSettingsLayout ref="installationSettingsLayout" @reset-server="setupModal?.show()">
 			<template #extra>
 				<div class="flex flex-col gap-2.5">
 					<span class="text-lg font-semibold text-contrast">{{
@@ -455,6 +455,9 @@ provideInstallationSettings({
 		debug('save: called with', { platform, gameVersion, loaderVersionId })
 		const currentPlatform = server.value?.loader?.toLowerCase() ?? 'vanilla'
 		const platformChanged = platform !== currentPlatform
+		const gameVersionChanged = gameVersion !== (server.value?.mc_version ?? '')
+		const loaderVersionChanged =
+			loaderVersionId !== null && loaderVersionId !== (server.value?.loader_version ?? '')
 
 		let resolvedLoaderVersion = loaderVersionId
 		if (!resolvedLoaderVersion && platform !== 'vanilla') {
@@ -465,12 +468,12 @@ provideInstallationSettings({
 		debug('save: emitting reinstall before API call')
 		emit(
 			'reinstall',
-			platformChanged
+			platformChanged || loaderVersionChanged
 				? { loader: platform, lVersion: resolvedLoaderVersion, mVersion: gameVersion }
 				: { mVersion: gameVersion },
 		)
 		try {
-			if (platformChanged) {
+			if (platformChanged || loaderVersionChanged) {
 				const request: Archon.Content.v1.InstallWorldContent = {
 					content_variant: 'bare',
 					loader: toApiLoader(platform),
@@ -478,9 +481,9 @@ provideInstallationSettings({
 					game_version: gameVersion || undefined,
 					soft_override: true,
 				}
-				debug('save: platform changed, calling installContent', request)
+				debug('save: platform/loader version changed, calling installContent', request)
 				await client.archon.content_v1.installContent(serverId, worldId.value!, request)
-			} else {
+			} else if (gameVersionChanged) {
 				debug('save: game version only, calling applyGameVersionUpdate', gameVersion)
 				await client.archon.content_v1.applyGameVersionUpdate(serverId, worldId.value!, gameVersion)
 			}
@@ -662,8 +665,66 @@ provideInstallationSettings({
 	isApp: false,
 	showModpackVersionActions: computed(() => modpack.value?.spec.platform === 'modrinth'),
 
-	lockPlatform: true,
-	hideLoaderVersion: true,
+	lockPlatform: false,
+	hideLoaderVersion: false,
+
+	async disableAllContent() {
+		debug('disableAllContent: fetching all addons')
+		const addons = await client.archon.content_v1.getAddons(serverId, worldId.value!)
+		const items = (addons.addons ?? [])
+			.filter((a) => !a.disabled)
+			.map((a) => ({ kind: a.kind, filename: a.filename }))
+		if (items.length > 0) {
+			debug('disableAllContent: disabling', items.length, 'addons')
+			await client.archon.content_v1.disableAddons(serverId, worldId.value!, items)
+		}
+		debug('disableAllContent: done')
+	},
+
+	async disableIncompatibleContent(diffs) {
+		debug('disableIncompatibleContent: processing', diffs.length, 'diffs')
+		const addons = await client.archon.content_v1.getAddons(serverId, worldId.value!)
+		const removedFiles = new Set(diffs.filter((d) => d.type === 'removed').map((d) => d.fileName))
+		const items = (addons.addons ?? [])
+			.filter((a) => !a.disabled && removedFiles.has(a.filename))
+			.map((a) => ({ kind: a.kind, filename: a.filename }))
+		if (items.length > 0) {
+			debug('disableIncompatibleContent: disabling', items.length, 'addons')
+			await client.archon.content_v1.disableAddons(serverId, worldId.value!, items)
+		}
+		debug('disableIncompatibleContent: done')
+	},
+
+	async saveWithoutAutoFix(platform, gameVersion, loaderVersionId) {
+		debug('saveWithoutAutoFix: called with', { platform, gameVersion, loaderVersionId })
+		let resolvedLoaderVersion = loaderVersionId
+		if (!resolvedLoaderVersion && platform !== 'vanilla') {
+			const versions = getLoaderVersionsForGameVersion(platform, gameVersion)
+			resolvedLoaderVersion = versions[0]?.id ?? null
+		}
+		emit('reinstall', { loader: platform, lVersion: resolvedLoaderVersion, mVersion: gameVersion })
+		try {
+			const request: Archon.Content.v1.InstallWorldContent = {
+				content_variant: 'bare',
+				loader: toApiLoader(platform),
+				version: resolvedLoaderVersion ?? '',
+				game_version: gameVersion || undefined,
+				soft_override: true,
+			}
+			debug('saveWithoutAutoFix: calling installContent', request)
+			await client.archon.content_v1.installContent(serverId, worldId.value!, request)
+			debug('saveWithoutAutoFix: succeeded, invalidating')
+			invalidateServerState()
+		} catch (err) {
+			debug('saveWithoutAutoFix: failed', err)
+			emit('reinstall-failed')
+			addNotification({
+				type: 'error',
+				text: err instanceof Error ? err.message : formatMessage(messages.failedToSaveSettings),
+			})
+			throw err
+		}
+	},
 
 	async previewSave(_platform, gameVersion, _loaderVersionId, signal) {
 		const result = await client.archon.content_v1.getUpdateGameVersionPreview(
diff --git a/packages/api-client/src/modules/archon/types.ts b/packages/api-client/src/modules/archon/types.ts
index 5c1380037..9c0c315f8 100644
--- a/packages/api-client/src/modules/archon/types.ts
+++ b/packages/api-client/src/modules/archon/types.ts
@@ -611,6 +611,11 @@ export namespace Archon {
 				percent: number
 			}
 
+			export type SyncContentError = {
+				step: string
+				description: string
+			}
+
 			export type WSStateEvent = {
 				event: 'state'
 				debug: string
@@ -620,6 +625,7 @@ export namespace Archon {
 				target: 'start' | 'stop' | 'restart' | null
 				uptime: number
 				progress: SyncContentProgress | null
+				content_error: SyncContentError | null
 			}
 
 			// Outgoing messages (client -> server)
diff --git a/packages/ui/src/components/flows/creation-flow-modal/components/ModpackStage.vue b/packages/ui/src/components/flows/creation-flow-modal/components/ModpackStage.vue
index 984af1063..ce3d086b9 100644
--- a/packages/ui/src/components/flows/creation-flow-modal/components/ModpackStage.vue
+++ b/packages/ui/src/components/flows/creation-flow-modal/components/ModpackStage.vue
@@ -147,6 +147,7 @@ watch(
 		// Always fetch the actual latest version from the API since search index can be stale
 		try {
 			const versions = await ctx.getProjectVersions(projectId)
+			if (ctx.modpackSearchProjectId.value !== projectId) return
 			if (versions.length > 0) {
 				const version = versions[0]
 				ctx.modpackSelection.value = {
diff --git a/packages/ui/src/components/flows/creation-flow-modal/creation-flow-context.ts b/packages/ui/src/components/flows/creation-flow-modal/creation-flow-context.ts
index b72d89311..f3f86fd00 100644
--- a/packages/ui/src/components/flows/creation-flow-modal/creation-flow-context.ts
+++ b/packages/ui/src/components/flows/creation-flow-modal/creation-flow-context.ts
@@ -307,8 +307,19 @@ export function createCreationFlowContext(
 		isImportMode.value = false
 		setupType.value = type
 		if (type === 'modpack') {
+			selectedLoader.value = null
+			selectedLoaderVersion.value = null
+			loaderVersionType.value = 'stable'
 			modal.value?.setStage('modpack')
 		} else {
+			modpackSelection.value = null
+			modpackFile.value = null
+			modpackFilePath.value = null
+			if (type === 'vanilla') {
+				selectedLoader.value = null
+				selectedLoaderVersion.value = null
+				loaderVersionType.value = 'stable'
+			}
 			// both custom and vanilla go to custom-setup
 			// vanilla just hides loader chips via hideLoaderChips computed
 			modal.value?.setStage('custom-setup')
diff --git a/packages/ui/src/components/servers/InstallingBanner.vue b/packages/ui/src/components/servers/InstallingBanner.vue
index 10ad0f671..661d465c6 100644
--- a/packages/ui/src/components/servers/InstallingBanner.vue
+++ b/packages/ui/src/components/servers/InstallingBanner.vue
@@ -1,12 +1,17 @@
 <template>
-	<Admonition type="info" show-actions-underneath>
+	<Admonition :type="contentError ? 'critical' : 'info'" :show-actions-underneath="!contentError">
 		<template #icon>
-			<slot name="icon">
+			<slot v-if="!contentError" name="icon">
 				<SpinnerIcon class="h-6 w-6 flex-none animate-spin text-brand-blue" />
 			</slot>
 		</template>
-		<template #header>We're preparing your server!</template>
-		<template v-if="progress">{{ phaseLabel }}</template>
+		<template #header>
+			{{ contentError ? 'Installation error' : "We're preparing your server!" }}
+		</template>
+		<template v-if="contentError">
+			{{ errorLabel }}
+		</template>
+		<template v-else-if="progress">{{ phaseLabel }}</template>
 		<div v-else class="ticker-container">
 			<div class="ticker-content">
 				<div
@@ -19,7 +24,15 @@
 				</div>
 			</div>
 		</div>
-		<template #actions>
+		<template v-if="contentError" #top-right-actions>
+			<ButtonStyled color="red" type="outlined">
+				<button class="!border" @click="emit('retry')">
+					<RotateCounterClockwiseIcon class="size-5" />
+					Retry
+				</button>
+			</ButtonStyled>
+		</template>
+		<template v-if="!contentError" #actions>
 			<ProgressBar
 				v-if="progress"
 				:progress="progress.percent"
@@ -33,10 +46,12 @@
 </template>
 
 <script setup lang="ts">
+import { RotateCounterClockwiseIcon } from '@modrinth/assets'
 import SpinnerIcon from '@modrinth/assets/icons/spinner.svg'
 import { computed, onMounted, onUnmounted, ref } from 'vue'
 
 import Admonition from '../base/Admonition.vue'
+import ButtonStyled from '../base/ButtonStyled.vue'
 import ProgressBar from '../base/ProgressBar.vue'
 
 export interface SyncProgress {
@@ -44,10 +59,48 @@ export interface SyncProgress {
 	percent: number
 }
 
+export interface ContentError {
+	step: string
+	description: string
+}
+
 const props = defineProps<{
 	progress?: SyncProgress | null
+	contentError?: ContentError | null
 }>()
 
+const emit = defineEmits<{
+	retry: []
+}>()
+
+const errorLabel = computed(() => {
+	const desc = props.contentError?.description?.toLowerCase()
+	const step = props.contentError?.step
+
+	if (step === 'modloader') {
+		if (desc === 'the specified version may be incorrect') {
+			return 'The specified loader or Minecraft version could not be installed. It may be invalid or unsupported.'
+		}
+		if (desc === 'this version is not yet supported') {
+			return 'This version of Minecraft or loader is not yet supported by Modrinth Hosting.'
+		}
+		if (desc === 'internal error') {
+			return 'An internal error occurred while installing the platform. Please try again.'
+		}
+	}
+
+	if (step === 'modpack') {
+		if (desc?.includes('no primary file')) {
+			return 'The modpack version has no downloadable file. It may have been packaged incorrectly.'
+		}
+		if (desc?.includes('failed to install')) {
+			return 'Failed to install the modpack. It may be corrupted or incompatible.'
+		}
+	}
+
+	return props.contentError?.description ?? 'An unexpected error occurred during installation.'
+})
+
 const phaseLabel = computed(() => {
 	switch (props.progress?.phase) {
 		case 'InstallingLoader':
diff --git a/packages/ui/src/layouts/shared/content-tab/components/ContentModpackCard.vue b/packages/ui/src/layouts/shared/content-tab/components/ContentModpackCard.vue
index 08e513f7c..8852af0ac 100644
--- a/packages/ui/src/layouts/shared/content-tab/components/ContentModpackCard.vue
+++ b/packages/ui/src/layouts/shared/content-tab/components/ContentModpackCard.vue
@@ -138,7 +138,7 @@ onUnmounted(() => {
 		class="@container flex flex-col gap-4 rounded-[20px] bg-bg-raised p-6 shadow-md"
 		:class="{ 'opacity-50': disabled }"
 	>
-		<div class="flex flex-wrap items-center justify-between gap-4">
+		<div class="flex flex-wrap items-start justify-between gap-4">
 			<div class="flex min-w-0 flex-1 items-center gap-4">
 				<AutoLink :to="projectLink" class="shrink-0">
 					<Avatar :src="project.icon_url" :alt="project.title" size="5rem" no-shadow raised />
diff --git a/packages/ui/src/layouts/shared/content-tab/components/modals/ConfirmBulkUpdateModal.vue b/packages/ui/src/layouts/shared/content-tab/components/modals/ConfirmBulkUpdateModal.vue
index 27ab518df..4cddbc452 100644
--- a/packages/ui/src/layouts/shared/content-tab/components/modals/ConfirmBulkUpdateModal.vue
+++ b/packages/ui/src/layouts/shared/content-tab/components/modals/ConfirmBulkUpdateModal.vue
@@ -13,6 +13,7 @@
 			<InlineBackupCreator
 				ref="backupCreator"
 				:backup-name="backupTip ? `Before bulk update (${backupTip})` : 'Before bulk update'"
+				:shift-click-hint-override="formatMessage(messages.shiftClickHint)"
 				@update:buttons-disabled="buttonsDisabled = $event"
 			/>
 		</div>
@@ -68,6 +69,11 @@ const messages = defineMessages({
 		id: 'content.confirm-bulk-update.update-button',
 		defaultMessage: 'Update {count, plural, one {# project} other {# projects}}',
 	},
+	shiftClickHint: {
+		id: 'content.confirm-bulk-update.shift-click-hint',
+		defaultMessage:
+			'Hold Shift while clicking "Update all" to skip this confirmation in the future.',
+	},
 })
 
 defineProps<{
diff --git a/packages/ui/src/layouts/shared/content-tab/components/modals/InlineBackupCreator.vue b/packages/ui/src/layouts/shared/content-tab/components/modals/InlineBackupCreator.vue
index ef1598ef4..f95db5667 100644
--- a/packages/ui/src/layouts/shared/content-tab/components/modals/InlineBackupCreator.vue
+++ b/packages/ui/src/layouts/shared/content-tab/components/modals/InlineBackupCreator.vue
@@ -44,7 +44,7 @@
 			/>
 		</div>
 		<span v-if="!props.hideShiftClickHint" class="text-secondary">
-			{{ formatMessage(messages.shiftClickHint) }}
+			{{ props.shiftClickHintOverride ?? formatMessage(messages.shiftClickHint) }}
 		</span>
 	</div>
 </template>
@@ -61,6 +61,7 @@ import { useInlineBackup } from '../../composables/use-inline-backup'
 const props = defineProps<{
 	backupName: string
 	hideShiftClickHint?: boolean
+	shiftClickHintOverride?: string
 }>()
 
 const emit = defineEmits<{
diff --git a/packages/ui/src/layouts/shared/installation-settings/components/ContentDiffModal.vue b/packages/ui/src/layouts/shared/installation-settings/components/ContentDiffModal.vue
index 48b81cfa0..131232582 100644
--- a/packages/ui/src/layouts/shared/installation-settings/components/ContentDiffModal.vue
+++ b/packages/ui/src/layouts/shared/installation-settings/components/ContentDiffModal.vue
@@ -73,6 +73,7 @@
 				<InlineBackupCreator
 					ref="backupCreator"
 					backup-name="Before version change"
+					hide-shift-click-hint
 					@update:buttons-disabled="buttonsDisabled = $event"
 				/>
 			</div>
diff --git a/packages/ui/src/layouts/shared/installation-settings/components/IncompatibleContentModal.vue b/packages/ui/src/layouts/shared/installation-settings/components/IncompatibleContentModal.vue
new file mode 100644
index 000000000..ea9e03e11
--- /dev/null
+++ b/packages/ui/src/layouts/shared/installation-settings/components/IncompatibleContentModal.vue
@@ -0,0 +1,194 @@
+<template>
+	<NewModal ref="modal" :header="formatMessage(messages.header)" :closable="!loading" no-padding>
+		<div class="flex max-w-[500px] flex-col gap-6 p-6">
+			<Admonition
+				:type="variant === 'loader-change' ? 'critical' : 'warning'"
+				:header="
+					variant === 'loader-change'
+						? formatMessage(messages.loaderChangeTitle)
+						: formatMessage(messages.gameVersionWarningTitle)
+				"
+			>
+				<div class="flex flex-col gap-3">
+					<span>
+						{{
+							variant === 'loader-change'
+								? formatMessage(messages.loaderChangeBody)
+								: formatMessage(messages.gameVersionWarningBody)
+						}}
+					</span>
+					<div v-if="variant === 'loader-change'">
+						<ButtonStyled color="red">
+							<button :disabled="loading" @click="handleResetServer">
+								<TrashIcon class="size-5" />
+								{{ formatMessage(commonMessages.resetServerButton) }}
+							</button>
+						</ButtonStyled>
+					</div>
+				</div>
+			</Admonition>
+
+			<InlineBackupCreator
+				ref="backupCreator"
+				:backup-name="
+					variant === 'loader-change' ? 'Before loader change' : 'Before version change'
+				"
+				hide-shift-click-hint
+				@update:buttons-disabled="buttonsDisabled = $event"
+			/>
+		</div>
+
+		<template #actions>
+			<div class="flex justify-end gap-2">
+				<ButtonStyled>
+					<button :disabled="loading" @click="handleCancel">
+						<XIcon />
+						{{ formatMessage(commonMessages.cancelButton) }}
+					</button>
+				</ButtonStyled>
+				<template v-if="variant === 'game-version-change'">
+					<ButtonStyled>
+						<button :disabled="buttonsDisabled || loading" @click="handleDisableConflicts">
+							<SpinnerIcon
+								v-if="loading && loadingAction === 'disable-conflicts'"
+								class="size-5 animate-spin"
+							/>
+							<PowerOffIcon v-else class="size-5" />
+							{{ formatMessage(messages.disableConflictsButton) }}
+						</button>
+					</ButtonStyled>
+					<ButtonStyled color="orange">
+						<button :disabled="buttonsDisabled || loading" @click="handleAutoFix">
+							<SpinnerIcon
+								v-if="loading && loadingAction === 'auto-fix'"
+								class="size-5 animate-spin"
+							/>
+							<HammerIcon v-else class="size-5" />
+							{{ formatMessage(messages.autoFixButton) }}
+						</button>
+					</ButtonStyled>
+				</template>
+				<template v-else>
+					<ButtonStyled color="red">
+						<button :disabled="buttonsDisabled || loading" @click="handleConfirmLoaderChange">
+							<SpinnerIcon v-if="loading" class="size-5 animate-spin" />
+							<CircleAlertIcon v-else class="size-5" />
+							{{ formatMessage(messages.changeLoaderButton) }}
+						</button>
+					</ButtonStyled>
+				</template>
+			</div>
+		</template>
+	</NewModal>
+</template>
+
+<script setup lang="ts">
+import {
+	CircleAlertIcon,
+	HammerIcon,
+	PowerOffIcon,
+	SpinnerIcon,
+	TrashIcon,
+	XIcon,
+} from '@modrinth/assets'
+import { ref } from 'vue'
+
+import Admonition from '#ui/components/base/Admonition.vue'
+import ButtonStyled from '#ui/components/base/ButtonStyled.vue'
+import NewModal from '#ui/components/modal/NewModal.vue'
+import { defineMessages, useVIntl } from '#ui/composables/i18n'
+import { commonMessages } from '#ui/utils/common-messages'
+
+import InlineBackupCreator from '../../content-tab/components/modals/InlineBackupCreator.vue'
+
+defineProps<{
+	variant: 'loader-change' | 'game-version-change'
+	loading?: boolean
+}>()
+
+const emit = defineEmits<{
+	'confirm-loader-change': []
+	'auto-fix': []
+	'disable-conflicts': []
+	'reset-server': []
+	cancel: []
+}>()
+
+const { formatMessage } = useVIntl()
+
+const modal = ref<InstanceType<typeof NewModal>>()
+const buttonsDisabled = ref(false)
+const loadingAction = ref<'auto-fix' | 'disable-conflicts' | null>(null)
+
+function show(e?: MouseEvent) {
+	loadingAction.value = null
+	modal.value?.show(e)
+}
+
+function hide() {
+	modal.value?.hide()
+}
+
+function handleCancel() {
+	hide()
+	emit('cancel')
+}
+
+function handleConfirmLoaderChange() {
+	emit('confirm-loader-change')
+}
+
+function handleAutoFix() {
+	loadingAction.value = 'auto-fix'
+	emit('auto-fix')
+}
+
+function handleDisableConflicts() {
+	loadingAction.value = 'disable-conflicts'
+	emit('disable-conflicts')
+}
+
+function handleResetServer() {
+	hide()
+	emit('reset-server')
+}
+
+const messages = defineMessages({
+	header: {
+		id: 'installation-settings.incompatible-content.header',
+		defaultMessage: 'Incompatible content installed',
+	},
+	loaderChangeTitle: {
+		id: 'installation-settings.incompatible-content.loader-change-title',
+		defaultMessage: 'Changing loaders is destructive',
+	},
+	loaderChangeBody: {
+		id: 'installation-settings.incompatible-content.loader-change-body',
+		defaultMessage:
+			'When changing the loader, all installed content will be disabled. We recommend resetting your server instead.',
+	},
+	gameVersionWarningTitle: {
+		id: 'installation-settings.incompatible-content.game-version-warning-title',
+		defaultMessage: 'Incompatibility warning',
+	},
+	gameVersionWarningBody: {
+		id: 'installation-settings.incompatible-content.game-version-warning-body',
+		defaultMessage:
+			'When changing the game version, we can either disable incompatible installed content or attempt to resolve the incompatibilities.',
+	},
+	changeLoaderButton: {
+		id: 'installation-settings.incompatible-content.change-loader-button',
+		defaultMessage: 'Change loader',
+	},
+	autoFixButton: {
+		id: 'installation-settings.incompatible-content.auto-fix-button',
+		defaultMessage: 'Auto-fix',
+	},
+	disableConflictsButton: {
+		id: 'installation-settings.incompatible-content.disable-conflicts-button',
+		defaultMessage: 'Disable conflicts',
+	},
+})
+
+defineExpose({ show, hide })
+</script>
diff --git a/packages/ui/src/layouts/shared/installation-settings/composables/index.ts b/packages/ui/src/layouts/shared/installation-settings/composables/index.ts
index 958d19a14..b779cd8a7 100644
--- a/packages/ui/src/layouts/shared/installation-settings/composables/index.ts
+++ b/packages/ui/src/layouts/shared/installation-settings/composables/index.ts
@@ -1 +1 @@
-export { useInstallationForm } from './use-installation-form'
+export { type IncompatibleContentVariant, useInstallationForm } from './use-installation-form'
diff --git a/packages/ui/src/layouts/shared/installation-settings/composables/use-installation-form.ts b/packages/ui/src/layouts/shared/installation-settings/composables/use-installation-form.ts
index cd5119928..16cc0fa52 100644
--- a/packages/ui/src/layouts/shared/installation-settings/composables/use-installation-form.ts
+++ b/packages/ui/src/layouts/shared/installation-settings/composables/use-installation-form.ts
@@ -6,13 +6,19 @@ import { formatLoaderLabel } from '#ui/utils/loaders'
 
 import type { ContentUpdaterModal } from '../../content-tab'
 import type ContentDiffModal from '../components/ContentDiffModal.vue'
+import type IncompatibleContentModal from '../components/IncompatibleContentModal.vue'
 import type { InstallationSettingsContext } from '../providers/installation-settings'
 import type { ContentDiffPreview } from '../types'
 
+export type IncompatibleContentVariant = 'loader-change' | 'game-version-change'
+
 export function useInstallationForm(
 	ctx: InstallationSettingsContext,
 	updaterModalRef: Ref<InstanceType<typeof ContentUpdaterModal> | null | undefined>,
 	contentDiffModalRef?: Ref<InstanceType<typeof ContentDiffModal> | null | undefined>,
+	incompatibleContentModalRef?: Ref<
+		InstanceType<typeof IncompatibleContentModal> | null | undefined
+	>,
 ) {
 	const isEditing = ref(false)
 	const selectedPlatform = ctx.editingPlatformRef ?? ref(ctx.currentPlatform.value)
@@ -22,6 +28,7 @@ export function useInstallationForm(
 	const isSaving = ref(false)
 	const isVerifying = ref(false)
 	const pendingPreview = ref<ContentDiffPreview | null>(null)
+	const incompatibleContentVariant = ref<IncompatibleContentVariant | null>(null)
 	let abortController: AbortController | null = null
 
 	const gameVersionOptions = computed(() =>
@@ -75,9 +82,26 @@ export function useInstallationForm(
 	async function save() {
 		isSaving.value = true
 		try {
+			const platformChanged = selectedPlatform.value !== ctx.currentPlatform.value
 			const isModded = ctx.currentPlatform.value !== 'vanilla'
 			const gameVersionChanged = selectedGameVersion.value !== ctx.currentGameVersion.value
 
+			if (platformChanged && ctx.disableAllContent) {
+				isSaving.value = false
+				incompatibleContentVariant.value = 'loader-change'
+				await nextTick()
+				incompatibleContentModalRef?.value?.show()
+				return
+			}
+
+			if (isModded && gameVersionChanged && ctx.disableIncompatibleContent) {
+				isSaving.value = false
+				incompatibleContentVariant.value = 'game-version-change'
+				await nextTick()
+				incompatibleContentModalRef?.value?.show()
+				return
+			}
+
 			if (ctx.previewSave && isModded && gameVersionChanged) {
 				isVerifying.value = true
 				abortController = new AbortController()
@@ -127,6 +151,111 @@ export function useInstallationForm(
 		}
 	}
 
+	async function confirmLoaderChange() {
+		try {
+			if (ctx.disableAllContent) {
+				await ctx.disableAllContent()
+			}
+			incompatibleContentVariant.value = null
+			await performSave()
+		} catch {
+			incompatibleContentVariant.value = null
+			isSaving.value = false
+		}
+	}
+
+	async function confirmAutoFix() {
+		try {
+			if (ctx.previewSave) {
+				isVerifying.value = true
+				abortController = new AbortController()
+				const loaderVersionId =
+					selectedPlatform.value !== 'vanilla'
+						? (loaderVersionEntries.value[selectedLoaderVersion.value]?.id ?? null)
+						: null
+
+				let preview: ContentDiffPreview | null
+				try {
+					preview = await ctx.previewSave(
+						selectedPlatform.value,
+						selectedGameVersion.value,
+						loaderVersionId,
+						abortController.signal,
+					)
+				} finally {
+					isVerifying.value = false
+					abortController = null
+				}
+
+				if (preview && (preview.diffs.length > 0 || preview.hasUnknownContent)) {
+					pendingPreview.value = preview
+					incompatibleContentVariant.value = null
+					await nextTick()
+					await nextTick()
+					contentDiffModalRef?.value?.show()
+					return
+				}
+			}
+
+			incompatibleContentVariant.value = null
+			await performSave()
+		} catch {
+			incompatibleContentVariant.value = null
+			isSaving.value = false
+		}
+	}
+
+	async function confirmDisableConflicts() {
+		try {
+			if (ctx.disableIncompatibleContent && ctx.previewSave) {
+				isVerifying.value = true
+				abortController = new AbortController()
+				const loaderVersionId =
+					selectedPlatform.value !== 'vanilla'
+						? (loaderVersionEntries.value[selectedLoaderVersion.value]?.id ?? null)
+						: null
+
+				let preview: ContentDiffPreview | null
+				try {
+					preview = await ctx.previewSave(
+						selectedPlatform.value,
+						selectedGameVersion.value,
+						loaderVersionId,
+						abortController.signal,
+					)
+				} finally {
+					isVerifying.value = false
+					abortController = null
+				}
+
+				if (preview) {
+					await ctx.disableIncompatibleContent(preview.diffs)
+				}
+			}
+
+			incompatibleContentVariant.value = null
+			if (ctx.saveWithoutAutoFix) {
+				const loaderVersionId =
+					selectedPlatform.value !== 'vanilla'
+						? (loaderVersionEntries.value[selectedLoaderVersion.value]?.id ?? null)
+						: null
+				await ctx.saveWithoutAutoFix(
+					selectedPlatform.value,
+					selectedGameVersion.value,
+					loaderVersionId,
+				)
+				if (ctx.afterSave) await ctx.afterSave()
+				isEditing.value = false
+				isSaving.value = false
+			} else {
+				await performSave()
+			}
+		} catch {
+			incompatibleContentVariant.value = null
+			isSaving.value = false
+		}
+	}
+
 	async function confirmSave() {
 		pendingPreview.value = null
 		try {
@@ -138,6 +267,7 @@ export function useInstallationForm(
 
 	function cancelPreview() {
 		pendingPreview.value = null
+		incompatibleContentVariant.value = null
 		isSaving.value = false
 	}
 
@@ -262,7 +392,11 @@ export function useInstallationForm(
 		hasChanges,
 		save,
 		pendingPreview,
+		incompatibleContentVariant,
 		confirmSave,
+		confirmLoaderChange,
+		confirmAutoFix,
+		confirmDisableConflicts,
 		cancelPreview,
 		cancelEditing,
 		updatingModpack,
diff --git a/packages/ui/src/layouts/shared/installation-settings/layout.vue b/packages/ui/src/layouts/shared/installation-settings/layout.vue
index 20a48f672..b54731a18 100644
--- a/packages/ui/src/layouts/shared/installation-settings/layout.vue
+++ b/packages/ui/src/layouts/shared/installation-settings/layout.vue
@@ -24,6 +24,7 @@ import Combobox from '#ui/components/base/Combobox.vue'
 import ConfirmLeaveModal from '#ui/components/modal/ConfirmLeaveModal.vue'
 import { defineMessages, useVIntl } from '#ui/composables/i18n'
 import { commonMessages } from '#ui/utils/common-messages'
+import { formatLoaderLabel } from '#ui/utils/loaders'
 
 import ConfirmModpackUpdateModal from '../content-tab/components/modals/ConfirmModpackUpdateModal.vue'
 import ConfirmReinstallModal from '../content-tab/components/modals/ConfirmReinstallModal.vue'
@@ -31,6 +32,7 @@ import ConfirmRepairModal from '../content-tab/components/modals/ConfirmRepairMo
 import ConfirmUnlinkModal from '../content-tab/components/modals/ConfirmUnlinkModal.vue'
 import ContentUpdaterModal from '../content-tab/components/modals/ContentUpdaterModal.vue'
 import ContentDiffModal from './components/ContentDiffModal.vue'
+import IncompatibleContentModal from './components/IncompatibleContentModal.vue'
 import { useInstallationForm } from './composables'
 import { injectInstallationSettings } from './providers/installation-settings'
 
@@ -44,11 +46,17 @@ const unlinkModal = ref<InstanceType<typeof ConfirmUnlinkModal>>()
 const contentUpdaterModal = ref<InstanceType<typeof ContentUpdaterModal> | null>()
 
 const contentDiffModal = ref<InstanceType<typeof ContentDiffModal>>()
+const incompatibleContentModal = ref<InstanceType<typeof IncompatibleContentModal>>()
 const modpackUpdateModal = ref<InstanceType<typeof ConfirmModpackUpdateModal>>()
 const pendingUpdateVersion = ref<Labrinth.Versions.v2.Version | null>(null)
 const isUpdateDowngrade = ref(false)
 
-const form = useInstallationForm(ctx, contentUpdaterModal, contentDiffModal)
+const form = useInstallationForm(
+	ctx,
+	contentUpdaterModal,
+	contentDiffModal,
+	incompatibleContentModal,
+)
 
 function handleBeforeUnload(e: BeforeUnloadEvent) {
 	if (form.isSaving.value) {
@@ -133,6 +141,16 @@ function handleUnlink() {
 	ctx.unlinkModpack()
 }
 
+const emit = defineEmits<{
+	'reset-server': []
+}>()
+
+function handleIncompatibleResetServer() {
+	form.cancelPreview()
+	form.cancelEditing()
+	emit('reset-server')
+}
+
 defineExpose({
 	cancelEditing: () => form.cancelEditing(),
 })
@@ -477,6 +495,8 @@ const messages = defineMessages({
 							<Chips
 								v-model="form.selectedPlatform.value"
 								:items="ctx.availablePlatforms"
+								:format-label="formatLoaderLabel"
+								:capitalize="false"
 								:disabled-items="disabledPlatforms"
 								:disabled-tooltip="formatMessage(messages.platformLockTooltip)"
 								:aria-label="formatMessage(messages.selectPlatformAriaLabel)"
@@ -708,8 +728,20 @@ const messages = defineMessages({
 			@unlink="handleUnlink"
 		/>
 
+		<IncompatibleContentModal
+			v-if="form.incompatibleContentVariant.value"
+			ref="incompatibleContentModal"
+			:variant="form.incompatibleContentVariant.value"
+			:loading="form.isVerifying.value || form.isSaving.value"
+			@confirm-loader-change="form.confirmLoaderChange()"
+			@auto-fix="form.confirmAutoFix()"
+			@disable-conflicts="form.confirmDisableConflicts()"
+			@reset-server="handleIncompatibleResetServer"
+			@cancel="form.cancelPreview()"
+		/>
+
 		<ContentDiffModal
-			v-if="form.pendingPreview.value"
+			v-if="form.pendingPreview.value && !form.incompatibleContentVariant.value"
 			ref="contentDiffModal"
 			:header="formatMessage(messages.confirmVersionChangeHeader)"
 			:description="
diff --git a/packages/ui/src/layouts/shared/installation-settings/providers/installation-settings.ts b/packages/ui/src/layouts/shared/installation-settings/providers/installation-settings.ts
index fc107b4f3..2fba0c559 100644
--- a/packages/ui/src/layouts/shared/installation-settings/providers/installation-settings.ts
+++ b/packages/ui/src/layouts/shared/installation-settings/providers/installation-settings.ts
@@ -4,6 +4,7 @@ import type { ComputedRef, Ref } from 'vue'
 import { createContext } from '#ui/providers/create-context'
 
 import type {
+	ContentDiffItem,
 	ContentDiffPreview,
 	GameVersionOption,
 	InstallationInfoRow,
@@ -61,6 +62,26 @@ export interface InstallationSettingsContext {
 
 	lockPlatform?: boolean
 	hideLoaderVersion?: boolean
+
+	/** Bulk-disable all addons on the server (used before switching loaders). */
+	disableAllContent?: () => Promise<void>
+
+	/**
+	 * Disable only the incompatible addons identified in a content diff preview.
+	 * Used when the user chooses "Disable conflicts" instead of "Auto-fix".
+	 */
+	disableIncompatibleContent?: (diffs: ContentDiffItem[]) => Promise<void>
+
+	/**
+	 * Save the installation settings without auto-resolving content.
+	 * Uses installContent with soft_override instead of applyGameVersionUpdate.
+	 */
+	saveWithoutAutoFix?: (
+		platform: string,
+		gameVersion: string,
+		loaderVersionId: string | null,
+	) => Promise<void>
+
 	previewSave?: (
 		platform: string,
 		gameVersion: string,
diff --git a/packages/ui/src/locales/en-US/index.json b/packages/ui/src/locales/en-US/index.json
index 78548f369..447fc9a42 100644
--- a/packages/ui/src/locales/en-US/index.json
+++ b/packages/ui/src/locales/en-US/index.json
@@ -233,6 +233,9 @@
   "content.confirm-bulk-update.header": {
     "defaultMessage": "Update projects"
   },
+  "content.confirm-bulk-update.shift-click-hint": {
+    "defaultMessage": "Hold Shift while clicking \"Update all\" to skip this confirmation in the future."
+  },
   "content.confirm-bulk-update.update-button": {
     "defaultMessage": "Update {count, plural, one {# project} other {# projects}}"
   },
@@ -977,6 +980,30 @@
   "installation-settings.edit.warning-server": {
     "defaultMessage": "We don't recommend editing your installation settings after installing content. If you want to edit them reset your server."
   },
+  "installation-settings.incompatible-content.auto-fix-button": {
+    "defaultMessage": "Auto-fix"
+  },
+  "installation-settings.incompatible-content.change-loader-button": {
+    "defaultMessage": "Change loader"
+  },
+  "installation-settings.incompatible-content.disable-conflicts-button": {
+    "defaultMessage": "Disable conflicts"
+  },
+  "installation-settings.incompatible-content.game-version-warning-body": {
+    "defaultMessage": "When changing the game version, we can either disable incompatible installed content or attempt to resolve the incompatibilities."
+  },
+  "installation-settings.incompatible-content.game-version-warning-title": {
+    "defaultMessage": "Incompatibility warning"
+  },
+  "installation-settings.incompatible-content.header": {
+    "defaultMessage": "Incompatible content installed"
+  },
+  "installation-settings.incompatible-content.loader-change-body": {
+    "defaultMessage": "When changing the loader, all installed content will be disabled. We recommend resetting your server instead."
+  },
+  "installation-settings.incompatible-content.loader-change-title": {
+    "defaultMessage": "Changing loaders is destructive"
+  },
   "installation-settings.linked-instance.title": {
     "defaultMessage": "Linked {projectType, select, server {server project} other {modpack}}"
   },
diff --git a/packages/ui/src/stories/servers/InstallingBanner.stories.ts b/packages/ui/src/stories/servers/InstallingBanner.stories.ts
new file mode 100644
index 000000000..f04431bc3
--- /dev/null
+++ b/packages/ui/src/stories/servers/InstallingBanner.stories.ts
@@ -0,0 +1,108 @@
+import type { Meta, StoryObj } from '@storybook/vue3-vite'
+
+import InstallingBanner from '../../components/servers/InstallingBanner.vue'
+
+const meta = {
+	title: 'Servers/InstallingBanner',
+	component: InstallingBanner,
+} satisfies Meta<typeof InstallingBanner>
+
+export default meta
+type Story = StoryObj<typeof meta>
+
+export const Default: Story = {
+	name: 'Default (no progress)',
+}
+
+export const WithProgress: Story = {
+	args: {
+		progress: {
+			phase: 'InstallingLoader',
+			percent: 45,
+		},
+	},
+}
+
+export const InstallingModpack: Story = {
+	args: {
+		progress: {
+			phase: 'InstallingPack',
+			percent: 72,
+		},
+	},
+}
+
+export const InstallingAddons: Story = {
+	args: {
+		progress: {
+			phase: 'Addons',
+			percent: 90,
+		},
+	},
+}
+
+export const ErrorInvalidVersion: Story = {
+	name: 'Error: Invalid Version',
+	args: {
+		contentError: {
+			step: 'modloader',
+			description: 'the specified version may be incorrect',
+		},
+	},
+}
+
+export const ErrorUnsupportedVersion: Story = {
+	name: 'Error: Unsupported Version',
+	args: {
+		contentError: {
+			step: 'modloader',
+			description: 'this version is not yet supported',
+		},
+	},
+}
+
+export const ErrorInternal: Story = {
+	name: 'Error: Internal',
+	args: {
+		contentError: {
+			step: 'modloader',
+			description: 'internal error',
+		},
+	},
+}
+
+export const ErrorModpackInstall: Story = {
+	name: 'Error: Modpack Install Failed',
+	args: {
+		contentError: {
+			step: 'modpack',
+			description: 'Failed to install modpack',
+		},
+	},
+}
+
+export const ErrorModpackNoFile: Story = {
+	name: 'Error: Modpack No Primary File',
+	args: {
+		contentError: {
+			step: 'modpack',
+			description: 'Modpack version has no primary file',
+		},
+	},
+}
+
+export const AllStates: Story = {
+	render: () => ({
+		components: { InstallingBanner },
+		template: /*html*/ `
+			<div style="display: flex; flex-direction: column; gap: 1rem;">
+				<InstallingBanner />
+				<InstallingBanner :progress="{ phase: 'InstallingLoader', percent: 45 }" />
+				<InstallingBanner :content-error="{ step: 'modloader', description: 'the specified version may be incorrect' }" />
+				<InstallingBanner :content-error="{ step: 'modloader', description: 'this version is not yet supported' }" />
+				<InstallingBanner :content-error="{ step: 'modloader', description: 'internal error' }" />
+				<InstallingBanner :content-error="{ step: 'modpack', description: 'Failed to install modpack' }" />
+			</div>
+		`,
+	}),
+}