Change Windows 10 File History drive
Solution 1:
From Backup settings (more options):
Back up to a different drive.
You'll need to stop using your current backup drive before you add a new one. This won't delete any files from your current backup.
- Open "Settings" app
- Open "Update and Security"
- Select "Backup" category
- Click "More options" under Backup using File History
- Scroll down to "Back up to a different drive"
- Click "Stop using drive"
- Go back to the main Backup window
- Click "Add a drive"
- Select the new drive
Source: How To Work With File History In Windows 10, From The Settings App