Hi 林宗昇,
Thank you for providing detailed information and for comparing your experience with other reports.
Based on what you've described, File History appears to continue copying updated files to the backup location, but the backup version history and timestamps shown in the File History interface may not be updating as expected after installing KB5101684. The fact that a new backup version is created only after reselecting the backup drive suggests the issue may be related to how File History is refreshing its backup catalog rather than a failure to back up the files themselves.
Since your backup drive is connected, File History is enabled, and the required service is running normally, there are currently no obvious configuration issues indicated by the information provided. As a temporary workaround, you may wish to periodically verify that updated files are appearing in the FileHistory folder and reselect the existing backup drive if a new backup version is not created automatically. Submitting feedback through Feedback Hub (Windows+F) can also help provide diagnostic information to the Windows engineering team for further investigation.
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.
In the meantime, continuing to monitor your backups and verifying that your files are being copied successfully is a good precaution.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.