Please click on the OneDrive icon on the taskbar, go to OneDrive Settings.
Click on the Account in the left pane of OneDrive settings, select 4 Hours in the "Lock Personal Vault after" drop menu for a check.
If personal vault still be locked frequently, I suggest you uninstall OneDrive and re-install it.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
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.