- Google Drive page
- Create a new Shared drive with the user as the Owner and do not share it with anyone.
- Make a right click on the shared rive and click on Shared drive settings.
- Remove the boxes for all shared drive settings.
- Click on Done.
- Move all files to the shared drive and then back to My Drive.
This will allow you to move all files to a new shared drive folder with all sharing settings disabled, and move these files back under My Drive to restrict access.