Update history shows KB5124008 successfully installed, yet Windows Update tells me to restart to install that update...

What is happening is consistent with a known Windows behavior: an update can show as successfully installed in Update history while Windows Update still temporarily says a restart is required. Microsoft documents that this can happen after installing an update, and that the restart-required indication can be temporary and resolve on its own.

Recommended steps:

1. Wait at least 15 minutes after the restart, then check again
   Microsoft documents a case where, after installing an update and restarting Windows, Settings > Update history can continue to indicate that a restart is required, and that this should resolve on its own after a short delay.
2. Confirm the update entry in Update history
   Go to Start > Settings > Windows Update > View update history and verify that KB5124008 is listed as installed.
3. If Windows Update still shows a pending restart, restart once more at a convenient time
   Go to Start > Settings > Update & Security > Windows Update and use Schedule the restart if needed. Microsoft notes that some update/install scenarios may require another restart to complete remaining changes.
4. Do not try to force-clear the restart state through the registry
   Microsoft explicitly warns against manually deleting or changing registry keys or values to work around repeated restart prompts, because that can cause later issues.
5. If the prompt persists, check for failed update entries or error codes
   In View update history, sort or review for any Failed updates and open the details for the error code if present. If there is an error, search that code through Microsoft Support.
6. If KB5124008 is also causing File History or other post-update problems, uninstalling that update has been reported as a workaround in Microsoft Q&A
   That Q&A specifically reports File History problems after KB5124008 and says uninstalling KB5124008 resolved the issue on affected PCs. Since the current issue described is USB audio, not File History, that workaround is only indirectly relevant.

For the USB audio problem: Microsoft has documented a separate Windows 10 issue where USB audio devices can initially get the standard USB audio 2.0 driver instead of the device-specific driver on first connection. That does not prove KB5124008 caused the current USB audio issue on this Windows 11 device, but it does show that Windows Update and USB audio driver behavior can interact.

• Resolved issues in Windows 11, version 25H2
• Windows Update: FAQ
• The computer needs to be restarted before Setup can continue in Exchange Server
• Windows Update or Microsoft Update repeatedly offers the same update
• File History problems after installing KB5124008, KB5126052, andKB890830 - Microsoft Q&A
• Windows 10 doesn't install specific drivers for USB audio devices on the first connection