diff --git a/ui/src/audioplayer/Player.jsx b/ui/src/audioplayer/Player.jsx
index c3d795b26..ecab5877c 100644
--- a/ui/src/audioplayer/Player.jsx
+++ b/ui/src/audioplayer/Player.jsx
@@ -49,6 +49,7 @@ const Player = () => {
   const stoppedRef = useRef(false)
   const [audioInstance, setAudioInstance] = useState(null)
   const isDesktop = useMediaQuery('(min-width:810px)')
+  const [playerMode, setPlayerMode] = useState('full')
   const isMobilePlayer =
     /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(
       navigator.userAgent,
@@ -56,6 +57,15 @@ const Player = () => {
 
   const { authenticated } = useAuthState()
 
+  // On desktop the player is the footer panel and `toggleMode` is disabled, so
+  // a player left collapsed while the window was narrow can never be reopened.
+  // Driving `mode` back to full on the transition restores the footer layout.
+  useEffect(() => {
+    if (isDesktop) {
+      setPlayerMode('full')
+    }
+  }, [isDesktop])
+
   // Keep a ref to playerState so the mount effect can read the latest value
   // without re-triggering on every queue/position change
   const playerStateRef = useRef(playerState)
@@ -207,7 +217,8 @@ const Player = () => {
       theme: playerTheme,
       bounds: 'body',
       playMode: playerState.mode,
-      mode: 'full',
+      mode: playerMode,
+      onModeChange: setPlayerMode,
       loadAudioErrorPlayNext: false,
       autoPlayInitLoadPlayList: true,
       clearPriorAudioLists: false,
@@ -236,7 +247,7 @@ const Player = () => {
       locale: locale(translate),
       sortableOptions: { delay: 200, delayOnTouchOnly: true },
     }),
-    [gainInfo, isDesktop, playerTheme, translate, playerState.mode],
+    [gainInfo, isDesktop, playerMode, playerTheme, translate, playerState.mode],
   )
 
   const options = useMemo(() => {
diff --git a/ui/src/audioplayer/Player.test.jsx b/ui/src/audioplayer/Player.test.jsx
new file mode 100644
index 000000000..63e7b6669
--- /dev/null
+++ b/ui/src/audioplayer/Player.test.jsx
@@ -0,0 +1,109 @@
+import React from 'react'
+import { render, act, cleanup } from '@testing-library/react'
+import { useMediaQuery } from '@material-ui/core'
+import { useAuthState } from 'react-admin'
+import { useSelector } from 'react-redux'
+import { Player } from './Player'
+
+// Captures the props the music player is rendered with, and exposes the
+// onModeChange callback so a test can simulate the user collapsing the player.
+const playerProps = { current: null }
+
+vi.mock('navidrome-music-player', () => ({
+  default: (props) => {
+    playerProps.current = props
+    return <div data-testid="music-player" />
+  },
+}))
+vi.mock('navidrome-music-player/assets/index.css', () => ({}))
+
+vi.mock('@material-ui/core', async () => {
+  const actual = await import('@material-ui/core')
+  return { ...actual, useMediaQuery: vi.fn() }
+})
+
+vi.mock('react-admin', async () => {
+  const actual = await import('react-admin')
+  return {
+    ...actual,
+    useAuthState: vi.fn(),
+    useDataProvider: () => ({ getOne: vi.fn().mockResolvedValue({}) }),
+    useTranslate: () => (key) => key,
+  }
+})
+
+vi.mock('react-redux', () => ({
+  useDispatch: () => vi.fn(),
+  useSelector: vi.fn(),
+}))
+
+vi.mock('../transcode', () => ({
+  detectBrowserProfile: () => ({}),
+  decisionService: {
+    setProfile: vi.fn(),
+    resolveStreamUrl: vi.fn().mockResolvedValue(''),
+    prefetchDecisions: vi.fn(),
+    invalidateAll: vi.fn(),
+  },
+}))
+
+vi.mock('./PlayerToolbar', () => ({ default: () => <div /> }))
+vi.mock('../subsonic', () => ({ default: { reportPlayback: vi.fn() } }))
+
+const state = {
+  player: {
+    queue: [{ trackId: 't1', uuid: 'u1', isRadio: false }],
+    playIndex: 0,
+    volume: 1,
+    mode: 'order',
+    current: { trackId: 't1' },
+    clear: false,
+    savedPlayIndex: 0,
+  },
+  settings: { notifications: false },
+  replayGain: { gainMode: 'none' },
+  theme: 'dark',
+}
+
+describe('<Player />', () => {
+  beforeEach(() => {
+    playerProps.current = null
+    useAuthState.mockReturnValue({ authenticated: true })
+    useSelector.mockImplementation((selector) => selector(state))
+  })
+
+  afterEach(cleanup)
+
+  // Regression test for #5917: a player collapsed while the window was narrow
+  // could never be reopened once the window grew past the desktop breakpoint,
+  // because toggleMode is disabled on desktop.
+  it('returns to full mode when the viewport grows into desktop', () => {
+    useMediaQuery.mockReturnValue(false)
+    const { rerender } = render(<Player />)
+    expect(playerProps.current.mode).toBe('full')
+
+    // The user collapses the player into the mini circle.
+    act(() => playerProps.current.onModeChange('mini'))
+    expect(playerProps.current.mode).toBe('mini')
+
+    // The window is widened past the desktop breakpoint.
+    useMediaQuery.mockReturnValue(true)
+    act(() => {
+      rerender(<Player />)
+    })
+
+    expect(playerProps.current.mode).toBe('full')
+  })
+
+  it('keeps the collapsed mode while the viewport stays narrow', () => {
+    useMediaQuery.mockReturnValue(false)
+    const { rerender } = render(<Player />)
+
+    act(() => playerProps.current.onModeChange('mini'))
+    act(() => {
+      rerender(<Player />)
+    })
+
+    expect(playerProps.current.mode).toBe('mini')
+  })
+})