diff --git a/app/api/admin/themes/__tests__/route.test.ts b/app/api/admin/themes/__tests__/route.test.ts
new file mode 100644
index 000000000..6f11c7a7d
--- /dev/null
+++ b/app/api/admin/themes/__tests__/route.test.ts
@@ -0,0 +1,50 @@
+/**
+ * @vitest-environment node
+ */
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { NextRequest } from 'next/server';
+
+vi.mock('@/lib/admin/session', () => ({
+  requireAdminAuth: vi.fn(async () => ({ session: { sub: 'admin' } })),
+  getClientIP: () => '127.0.0.1',
+}));
+vi.mock('@/lib/admin/audit', () => ({ auditLog: vi.fn(async () => {}) }));
+
+let policy: Record<string, unknown>;
+vi.mock('@/lib/admin/config-manager', () => ({
+  configManager: {
+    ensureLoaded: vi.fn(async () => {}),
+    get: vi.fn(),
+    getPolicy: vi.fn(() => policy),
+    setPolicy: vi.fn(async (p: Record<string, unknown>) => { policy = p; }),
+  },
+}));
+vi.mock('@/lib/admin/plugin-registry', () => ({
+  deleteTheme: vi.fn(async () => true),
+  saveTheme: vi.fn(),
+  getTheme: vi.fn(async () => null),
+  getThemeRegistry: vi.fn(async () => ({ themes: [] })),
+}));
+
+import { DELETE } from '../route';
+
+function del(id: string) {
+  return DELETE(new NextRequest('http://localhost/api/admin/themes', {
+    method: 'DELETE',
+    body: JSON.stringify({ id }),
+    headers: { 'content-type': 'application/json' },
+  }));
+}
+
+beforeEach(() => {
+  policy = { forceEnabledThemes: ['corp', 'other'], forceEnabledPlugins: [] };
+});
+
+describe('DELETE /api/admin/themes', () => {
+  it('stops forcing a theme once it is deleted', async () => {
+    const res = await del('corp');
+
+    expect(res.status).toBe(200);
+    expect(policy.forceEnabledThemes).toEqual(['other']);
+  });
+});
diff --git a/app/api/admin/themes/route.ts b/app/api/admin/themes/route.ts
index f600d09b6..a7869c0c1 100644
--- a/app/api/admin/themes/route.ts
+++ b/app/api/admin/themes/route.ts
@@ -8,6 +8,7 @@ import {
   deleteTheme as removeTheme,
   type ServerTheme,
 } from '@/lib/admin/plugin-registry';
+import { forgetExtensionInPolicy } from '@/lib/admin/extension-cleanup';
 
 import JSZip from 'jszip';
 import { MAX_THEME_SIZE } from '@/lib/plugin-types';
@@ -205,6 +206,7 @@ export async function DELETE(request: NextRequest) {
     if (!removed) {
       return NextResponse.json({ error: 'Theme not found' }, { status: 404 });
     }
+    await forgetExtensionInPolicy('theme', id);
 
     await auditLog('theme.delete', { id }, ip);
     return NextResponse.json({ success: true });
diff --git a/lib/__tests__/theme-store-sync.test.ts b/lib/__tests__/theme-store-sync.test.ts
new file mode 100644
index 000000000..824fc059f
--- /dev/null
+++ b/lib/__tests__/theme-store-sync.test.ts
@@ -0,0 +1,62 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+
+const serverThemes: { themes: unknown[] } = { themes: [] };
+vi.mock('@/lib/browser-navigation', async (orig) => ({
+  ...(await orig<typeof import('@/lib/browser-navigation')>()),
+  apiFetch: vi.fn(async () => new Response(JSON.stringify({ plugins: [], ...serverThemes }))),
+}));
+vi.mock('@/lib/plugin-storage', () => ({
+  pluginStorage: {
+    saveThemeCSS: vi.fn(async () => {}),
+    getThemeCSS: vi.fn(async () => null),
+    deleteThemeCSS: vi.fn(async () => {}),
+    deleteThemeSkin: vi.fn(async () => {}),
+    deletePreview: vi.fn(async () => {}),
+    getThemeSkin: vi.fn(async () => null),
+  },
+}));
+
+import { useThemeStore } from '@/stores/theme-store';
+import { pluginStorage } from '@/lib/plugin-storage';
+import type { InstalledTheme } from '@/lib/plugin-types';
+
+const CORP: InstalledTheme = {
+  id: 'corp', name: 'Corp', version: '1.0.0', author: 'IT', description: '',
+  css: ':root{--color-primary:red}', variants: ['light', 'dark'],
+  enabled: true, builtIn: false, managed: true, forceEnabled: true,
+};
+
+beforeEach(() => {
+  serverThemes.themes = [];
+  const builtIns = useThemeStore.getState().installedThemes.filter((t) => t.builtIn);
+  useThemeStore.setState({ installedThemes: [...builtIns, CORP], activeThemeId: 'corp' });
+});
+
+describe('server theme sync', () => {
+  it('drops a managed theme the admin deleted, and stops forcing it', async () => {
+    await useThemeStore.getState().syncServerThemes();
+
+    const state = useThemeStore.getState();
+    expect(state.installedThemes.some((t) => t.id === 'corp')).toBe(false);
+    expect(state.activeThemeId).toBeNull();
+    expect(pluginStorage.deleteThemeCSS).toHaveBeenCalledWith('corp');
+  });
+
+  it('keeps a theme the user installed themselves', async () => {
+    const mine: InstalledTheme = { ...CORP, id: 'mine', managed: false, forceEnabled: false };
+    useThemeStore.setState((s) => ({ installedThemes: [...s.installedThemes, mine] }));
+
+    await useThemeStore.getState().syncServerThemes();
+
+    expect(useThemeStore.getState().installedThemes.some((t) => t.id === 'mine')).toBe(true);
+  });
+
+  it('leaves everything alone when the server list could not be read', async () => {
+    const { apiFetch } = await import('@/lib/browser-navigation');
+    vi.mocked(apiFetch).mockResolvedValueOnce(new Response('nope', { status: 500 }));
+
+    await useThemeStore.getState().syncServerThemes();
+
+    expect(useThemeStore.getState().installedThemes.some((t) => t.id === 'corp')).toBe(true);
+  });
+});
diff --git a/lib/admin/extension-cleanup.ts b/lib/admin/extension-cleanup.ts
new file mode 100644
index 000000000..052e4a2f8
--- /dev/null
+++ b/lib/admin/extension-cleanup.ts
@@ -0,0 +1,15 @@
+import { configManager } from './config-manager';
+
+/**
+ * Drop a deleted plugin or theme from the policy lists that refer to it by
+ * id. Left behind, a later upload that reuses the id would start out forced
+ * on for everyone without the admin asking for it.
+ */
+export async function forgetExtensionInPolicy(kind: 'plugin' | 'theme', id: string): Promise<void> {
+  await configManager.ensureLoaded();
+  const policy = configManager.getPolicy();
+  const key = kind === 'plugin' ? 'forceEnabledPlugins' : 'forceEnabledThemes';
+  const list = policy[key] ?? [];
+  if (!list.includes(id)) return;
+  await configManager.setPolicy({ ...policy, [key]: list.filter((x) => x !== id) });
+}
diff --git a/stores/theme-store.ts b/stores/theme-store.ts
index e9ad9da78..3427dc5ea 100644
--- a/stores/theme-store.ts
+++ b/stores/theme-store.ts
@@ -418,6 +418,29 @@ export const useThemeStore = create<ThemeState>()(
               }
             }
 
+            // A managed theme the server no longer lists was deleted or
+            // disabled by the admin. Without this it stayed installed, and
+            // its local forceEnabled flag kept forcing it on forever.
+            const serverIds = new Set(serverThemes.map(t => t.id));
+            const stale = get().installedThemes.filter(t => t.managed && !t.builtIn && !serverIds.has(t.id));
+            if (stale.length > 0) {
+              const staleIds = new Set(stale.map(t => t.id));
+              const activeId = get().activeThemeId;
+              if (activeId && staleIds.has(activeId)) {
+                removeThemeCSS();
+                removeThemeSkinCSS();
+                set({ activeThemeId: null });
+              }
+              for (const id of staleIds) {
+                void pluginStorage.deleteThemeCSS(id);
+                void pluginStorage.deleteThemeSkin(id);
+                void pluginStorage.deletePreview(id);
+              }
+              set(state => ({
+                installedThemes: state.installedThemes.filter(t => !staleIds.has(t.id)),
+              }));
+            }
+
             set(state => ({
               installedThemes: dedupeInstalledThemes(state.installedThemes),
             }));