Quick fix: Focus session length persists across launches via HKCU\Software\Microsoft\Windows\CurrentVersion\Notifications\Settings\Windows.SystemToast.FocusSession — but a 24H2 bug resets it. Workaround: pin a specific length via registry value SessionLengthMinutes = your desired duration as DWORD.

You set Focus sessions (Clock app) to 45 minutes. Start a session, complete it. Open Focus again next day — reset to default 30 minutes. The customization didn’t persist between sessions on certain Windows builds.

Symptom: Focus session length resets to default after each session on Windows 11.
Affects: Windows 11 24H2 with Clock app Focus.
Fix time: 5 minutes.

What stores Focus session preferences

Focus sessions are part of the Windows Clock app, which uses a per-app local state file at %LocalAppData%\Packages\Microsoft.WindowsAlarms_8wekyb3d8bbwe\LocalState. A registry overlay in HKCU\Software\Microsoft\Windows\CurrentVersion\Notifications\Settings\Windows.SystemToast.FocusSession influences notification behavior. A 24H2 build bug clears the length pref when the session ends.

Method 1: Pin session length via registry

Open regedit.
Navigate to HKCU\Software\Microsoft\Windows\CurrentVersion\Notifications\Settings\Windows.SystemToast.FocusSession.
Create DWORD SessionLengthMinutes = your value (e.g., 45).
Restart the Clock app.

Method 2: Update Clock app

Open Microsoft Store → Library → Get updates.
Update Clock app if available.
The persistence bug is fixed in newer versions.

Method 3: Use a third-party Pomodoro timer

For chronic Focus issues, install a dedicated app like Pomotroid, Forest, or FocusKeeper from the Store.
These respect their own settings reliably.

Verification

Open Clock app. Focus session shows your set length.
Complete a session. Open again. Same length persists.

If none of these work

For chronic resets, the Clock app’s LocalState may be corrupted — reset the app via Settings → Apps → Installed apps → Clock → Advanced options → Reset.

Bottom line: Focus session reset is a Clock app bug. Pin via registry or update the app. Third-party alternatives offer more durable customization.