diff --git a/src/renderer/src/store/slices/worktrees.test.ts b/src/renderer/src/store/slices/worktrees.test.ts
index 8adfddd8140..3616acb77a4 100644
--- a/src/renderer/src/store/slices/worktrees.test.ts
+++ b/src/renderer/src/store/slices/worktrees.test.ts
@@ -88,6 +88,7 @@ import {
   registerPersistentWebview,
   unregisterPersistentWebview
 } from '../../components/browser-pane/webview-registry'
+import { FLOATING_TERMINAL_WORKTREE_ID } from '../../../../shared/constants'
 
 function resetRemoteRuntimeMocks() {
   clearRuntimeCompatibilityCacheForTests()
@@ -3243,6 +3244,117 @@ describe('fetchAllWorktrees hydration-time purge (design §4.4)', () => {
     })
     expect(store.getState().hasHydratedWorktreePurge).toBe(true)
   })
+
+  it('preserves floating workspace state while purging a real stale worktree', async () => {
+    const store = createTestStore()
+    const wtA = makeWorktree({ id: 'repoA::/a/wt1', repoId: 'repoA', path: '/a/wt1' })
+    const wtB = makeWorktree({ id: 'repoB::/b/wt1', repoId: 'repoB', path: '/b/wt1' })
+    const staleId = 'repoA::/a/zombie'
+    const floatingFile = {
+      id: 'floating-file',
+      worktreeId: FLOATING_TERMINAL_WORKTREE_ID,
+      filePath: '/floating/note.md',
+      relativePath: 'note.md',
+      language: 'markdown',
+      isDirty: false,
+      isPreview: false,
+      mode: 'edit' as const
+    }
+
+    mockApi.worktrees.list.mockImplementation(async ({ repoId }: { repoId: string }) =>
+      repoId === 'repoA' ? [wtA] : [wtB]
+    )
+
+    store.setState({
+      repos: [repoA, repoB],
+      activeWorktreeId: FLOATING_TERMINAL_WORKTREE_ID,
+      activeFileId: 'floating-file',
+      activeTabId: 'floating-terminal-tab',
+      activeTabType: 'editor' as const,
+      tabsByWorktree: {
+        [wtA.id]: [{ id: 'tab-A', worktreeId: wtA.id }],
+        [staleId]: [{ id: 'tab-zombie', worktreeId: staleId }],
+        [FLOATING_TERMINAL_WORKTREE_ID]: [
+          { id: 'floating-terminal-tab', worktreeId: FLOATING_TERMINAL_WORKTREE_ID }
+        ]
+      },
+      browserTabsByWorktree: {
+        [FLOATING_TERMINAL_WORKTREE_ID]: [{ id: 'floating-browser', url: 'https://orca.test' }]
+      },
+      activeBrowserTabIdByWorktree: {
+        [FLOATING_TERMINAL_WORKTREE_ID]: 'floating-browser'
+      },
+      openFiles: [
+        floatingFile,
+        {
+          id: 'stale-file',
+          worktreeId: staleId,
+          filePath: '/a/zombie/stale.ts',
+          relativePath: 'stale.ts',
+          language: 'typescript',
+          isDirty: false,
+          isPreview: false,
+          mode: 'edit' as const
+        }
+      ],
+      activeFileIdByWorktree: {
+        [FLOATING_TERMINAL_WORKTREE_ID]: 'floating-file',
+        [staleId]: 'stale-file'
+      },
+      unifiedTabsByWorktree: {
+        [FLOATING_TERMINAL_WORKTREE_ID]: [
+          {
+            id: 'floating-unified-tab',
+            type: 'editor',
+            worktreeId: FLOATING_TERMINAL_WORKTREE_ID,
+            fileId: 'floating-file'
+          }
+        ],
+        [staleId]: [{ id: 'stale-unified-tab', worktreeId: staleId }]
+      },
+      groupsByWorktree: {
+        [FLOATING_TERMINAL_WORKTREE_ID]: [
+          {
+            id: 'floating-group',
+            worktreeId: FLOATING_TERMINAL_WORKTREE_ID,
+            activeTabId: 'floating-unified-tab'
+          }
+        ],
+        [staleId]: [{ id: 'stale-group', worktreeId: staleId, activeTabId: 'stale-unified-tab' }]
+      },
+      layoutByWorktree: {
+        [FLOATING_TERMINAL_WORKTREE_ID]: { type: 'leaf', groupId: 'floating-group' },
+        [staleId]: { type: 'leaf', groupId: 'stale-group' }
+      }
+    } as unknown as Partial<AppState>)
+
+    await store.getState().fetchAllWorktrees()
+
+    expect(store.getState().hasHydratedWorktreePurge).toBe(true)
+    expect(store.getState().tabsByWorktree).toEqual({
+      [wtA.id]: [{ id: 'tab-A', worktreeId: wtA.id }],
+      [FLOATING_TERMINAL_WORKTREE_ID]: [
+        { id: 'floating-terminal-tab', worktreeId: FLOATING_TERMINAL_WORKTREE_ID }
+      ]
+    })
+    expect(store.getState().browserTabsByWorktree[FLOATING_TERMINAL_WORKTREE_ID]).toEqual([
+      { id: 'floating-browser', url: 'https://orca.test' }
+    ])
+    expect(store.getState().openFiles).toEqual([floatingFile])
+    expect(store.getState().activeFileIdByWorktree[FLOATING_TERMINAL_WORKTREE_ID]).toBe(
+      'floating-file'
+    )
+    expect(store.getState().unifiedTabsByWorktree[FLOATING_TERMINAL_WORKTREE_ID]).toHaveLength(1)
+    expect(store.getState().groupsByWorktree[FLOATING_TERMINAL_WORKTREE_ID]).toHaveLength(1)
+    expect(store.getState().layoutByWorktree[FLOATING_TERMINAL_WORKTREE_ID]).toEqual({
+      type: 'leaf',
+      groupId: 'floating-group'
+    })
+    expect(store.getState().activeWorktreeId).toBe(FLOATING_TERMINAL_WORKTREE_ID)
+    expect(store.getState().activeFileId).toBe('floating-file')
+    expect(store.getState().activeTabId).toBe('floating-terminal-tab')
+    expect(store.getState().activeTabType).toBe('editor')
+  })
 })
 
 // Why: design §4.4 — purgeWorktreeTerminalState wipes every worktree-scoped
@@ -3342,6 +3454,157 @@ describe('purgeWorktreeTerminalState direct (design §4.4)', () => {
 
     expect(store.getState().tabsByWorktree).toBe(before)
   })
+
+  it('ignores the floating workspace sentinel while purging mixed real ids', () => {
+    const store = createTestStore()
+    const staleId = 'repoA::/a/wt1'
+    const floatingFile = {
+      id: 'floating-file',
+      worktreeId: FLOATING_TERMINAL_WORKTREE_ID,
+      filePath: '/floating/note.md',
+      relativePath: 'note.md',
+      language: 'markdown',
+      isDirty: false,
+      isPreview: false,
+      mode: 'edit' as const
+    }
+
+    store.setState({
+      tabsByWorktree: {
+        [staleId]: [{ id: 'tab-1', worktreeId: staleId }],
+        [FLOATING_TERMINAL_WORKTREE_ID]: [
+          { id: 'floating-terminal-tab', worktreeId: FLOATING_TERMINAL_WORKTREE_ID }
+        ]
+      },
+      browserTabsByWorktree: {
+        [FLOATING_TERMINAL_WORKTREE_ID]: [{ id: 'floating-browser', url: 'https://orca.test' }]
+      },
+      openFiles: [
+        floatingFile,
+        {
+          id: 'stale-file',
+          worktreeId: staleId,
+          filePath: '/a/wt1/stale.ts',
+          relativePath: 'stale.ts',
+          language: 'typescript',
+          isDirty: false,
+          isPreview: false,
+          mode: 'edit' as const
+        }
+      ],
+      activeFileIdByWorktree: {
+        [FLOATING_TERMINAL_WORKTREE_ID]: 'floating-file',
+        [staleId]: 'stale-file'
+      },
+      unifiedTabsByWorktree: {
+        [FLOATING_TERMINAL_WORKTREE_ID]: [
+          {
+            id: 'floating-unified-tab',
+            type: 'editor',
+            worktreeId: FLOATING_TERMINAL_WORKTREE_ID,
+            fileId: 'floating-file'
+          }
+        ],
+        [staleId]: [{ id: 'stale-unified-tab', worktreeId: staleId }]
+      },
+      groupsByWorktree: {
+        [FLOATING_TERMINAL_WORKTREE_ID]: [
+          {
+            id: 'floating-group',
+            worktreeId: FLOATING_TERMINAL_WORKTREE_ID,
+            activeTabId: 'floating-unified-tab'
+          }
+        ],
+        [staleId]: [{ id: 'stale-group', worktreeId: staleId, activeTabId: 'stale-unified-tab' }]
+      },
+      layoutByWorktree: {
+        [FLOATING_TERMINAL_WORKTREE_ID]: { type: 'leaf', groupId: 'floating-group' },
+        [staleId]: { type: 'leaf', groupId: 'stale-group' }
+      }
+    } as unknown as Partial<AppState>)
+
+    store.getState().purgeWorktreeTerminalState([staleId, FLOATING_TERMINAL_WORKTREE_ID])
+
+    expect(store.getState().tabsByWorktree).toEqual({
+      [FLOATING_TERMINAL_WORKTREE_ID]: [
+        { id: 'floating-terminal-tab', worktreeId: FLOATING_TERMINAL_WORKTREE_ID }
+      ]
+    })
+    expect(store.getState().browserTabsByWorktree[FLOATING_TERMINAL_WORKTREE_ID]).toEqual([
+      { id: 'floating-browser', url: 'https://orca.test' }
+    ])
+    expect(store.getState().openFiles).toEqual([floatingFile])
+    expect(store.getState().activeFileIdByWorktree).toEqual({
+      [FLOATING_TERMINAL_WORKTREE_ID]: 'floating-file'
+    })
+    expect(store.getState().unifiedTabsByWorktree[FLOATING_TERMINAL_WORKTREE_ID]).toHaveLength(1)
+    expect(store.getState().groupsByWorktree[FLOATING_TERMINAL_WORKTREE_ID]).toHaveLength(1)
+    expect(store.getState().layoutByWorktree[FLOATING_TERMINAL_WORKTREE_ID]).toEqual({
+      type: 'leaf',
+      groupId: 'floating-group'
+    })
+  })
+
+  it('is a no-op when only the floating workspace sentinel is passed', () => {
+    const store = createTestStore()
+    const tabsByWorktree = {}
+    const browserTabsByWorktree = {
+      [FLOATING_TERMINAL_WORKTREE_ID]: [{ id: 'floating-browser', url: 'https://orca.test' }]
+    }
+    const openFiles = [
+      {
+        id: 'floating-file',
+        worktreeId: FLOATING_TERMINAL_WORKTREE_ID,
+        filePath: '/floating/note.md',
+        relativePath: 'note.md',
+        language: 'markdown',
+        isDirty: false,
+        isPreview: false,
+        mode: 'edit' as const
+      }
+    ]
+    const unifiedTabsByWorktree = {
+      [FLOATING_TERMINAL_WORKTREE_ID]: [
+        {
+          id: 'floating-unified-tab',
+          type: 'editor',
+          worktreeId: FLOATING_TERMINAL_WORKTREE_ID,
+          fileId: 'floating-file'
+        }
+      ]
+    }
+    const groupsByWorktree = {
+      [FLOATING_TERMINAL_WORKTREE_ID]: [
+        {
+          id: 'floating-group',
+          worktreeId: FLOATING_TERMINAL_WORKTREE_ID,
+          activeTabId: 'floating-unified-tab'
+        }
+      ]
+    }
+    const layoutByWorktree = {
+      [FLOATING_TERMINAL_WORKTREE_ID]: { type: 'leaf', groupId: 'floating-group' }
+    }
+
+    store.setState({
+      tabsByWorktree,
+      browserTabsByWorktree,
+      openFiles,
+      activeFileIdByWorktree: { [FLOATING_TERMINAL_WORKTREE_ID]: 'floating-file' },
+      unifiedTabsByWorktree,
+      groupsByWorktree,
+      layoutByWorktree
+    } as unknown as Partial<AppState>)
+
+    store.getState().purgeWorktreeTerminalState([FLOATING_TERMINAL_WORKTREE_ID])
+
+    expect(store.getState().tabsByWorktree).toBe(tabsByWorktree)
+    expect(store.getState().browserTabsByWorktree).toBe(browserTabsByWorktree)
+    expect(store.getState().openFiles).toBe(openFiles)
+    expect(store.getState().unifiedTabsByWorktree).toBe(unifiedTabsByWorktree)
+    expect(store.getState().groupsByWorktree).toBe(groupsByWorktree)
+    expect(store.getState().layoutByWorktree).toBe(layoutByWorktree)
+  })
 })
 
 describe('markWorktreeVisited', () => {
diff --git a/src/renderer/src/store/slices/worktrees.ts b/src/renderer/src/store/slices/worktrees.ts
index c09dd812fe4..461415c6402 100644
--- a/src/renderer/src/store/slices/worktrees.ts
+++ b/src/renderer/src/store/slices/worktrees.ts
@@ -45,6 +45,7 @@ import {
   parseExecutionHostId,
   type ExecutionHostId
 } from '../../../../shared/execution-host'
+import { FLOATING_TERMINAL_WORKTREE_ID } from '../../../../shared/constants'
 export type { WorktreeSlice, WorktreeDeleteState } from './worktree-helpers'
 
 // Why: old runtime servers only have `worktree.list`; preserve the large-list
@@ -940,6 +941,9 @@ export const createWorktreeSlice: StateCreator<AppState, [], [], WorktreeSlice>
       return
     }
     const validIds = new Set<string>()
+    // Why: floating is persisted renderer state, but not a repo worktree that
+    // authoritative runtime scans can return.
+    validIds.add(FLOATING_TERMINAL_WORKTREE_ID)
     for (const result of Object.values(get().detectedWorktreesByRepo)) {
       if (!result.authoritative) {
         continue
@@ -2556,9 +2560,10 @@ export const createWorktreeSlice: StateCreator<AppState, [], [], WorktreeSlice>
   getKnownWorktreeById: (worktreeId) => findKnownWorktreeById(get(), worktreeId),
 
   purgeWorktreeTerminalState: (worktreeIds: string[]) => {
-    if (worktreeIds.length === 0) {
+    const purgeableWorktreeIds = worktreeIds.filter((id) => id !== FLOATING_TERMINAL_WORKTREE_ID)
+    if (purgeableWorktreeIds.length === 0) {
       return
     }
-    set((s) => buildWorktreePurgeState(s, worktreeIds))
+    set((s) => buildWorktreePurgeState(s, purgeableWorktreeIds))
   }
 })