Hi HDVA,
Based on the information provided, it appears the notification subsystem may no longer be registering applications correctly after the registry modification. Since you've already completed extensive repairs, including SFC, DISM, an in-place upgrade, testing a new user profile, and even reinstalling Windows, the issue is likely tied to a deeper system configuration that was not rebuilt during those processes.
You may want to try the following additional checks:
1, Verify the Windows Push Notification Service
- Press Win + R, type
services.msc - Locate Windows Push Notifications System Service.
- Confirm it is present, running, and set to its default startup type.
2, Check Notification Registry Entries
- If you have a backup of the registry or know the exact key that was removed, compare it with a working Windows 11 system.
- Restoring the original key may help rebuild notification registrations.
3, Test from a Clean Installation Environment
- If possible, perform a clean Windows installation without restoring previous settings or profiles.
- Before installing additional software, check whether apps appear under Settings > Notifications.
If notification-capable apps still do not appear in the Notifications settings page after these checks, the issue may require further investigation by Microsoft Support, as it affects the core notification framework rather than a specific application.
Please note that this is a user-to-user support forum. Moderators, contributors including external Microsoft employees cannot directly intervene in Microsoft product features or access back-end systems. Our role is limited to providing technical guidance on reported issues, requests, or ideas.
Let me know if you need further assistance, feel free to ask me by clicking "Add Comment" or "Add Answer" if you cannot add comment so your response will be visible. Thanks for your effort.
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