Windows 11 File History

The working new drive and failing old target suggest two issues worth separating: backup destination handling and the encryption warning. BitLocker encrypts a volume; EFS encrypts individual files. Decrypting C: with BitLocker therefore does not necessarily remove EFS encryption.

Run cipher /u /n to identify encrypted files without updating their keys. If EFS files exist, preserve their certificate and private key before changing encryption; cipher /x backs up the current user’s EFS credentials. Keep using the working destination and test restoring a file. For the old drive, use Control Panel’s File History settings and Select drive rather than selecting its existing backup subfolder. Do not format or delete that backup while investigating. Automatic Device Encryption can activate on eligible devices during account setup, but that does not prove what happened here. The old target’s exact error is still needed to diagnose its failure.