External drives · Drive formats
Does FileVault encrypt my external fast drive too?
Short answer: No — FileVault only covers your internal disk. Files moved to an external drive are protected only if that drive is encrypted, so encrypt it in Finder (right-click → Encrypt) or erase it as APFS (Encrypted).
No. FileVault encrypts your Mac's internal startup disk only. Files you move to an external drive are protected by that drive's own encryption — so if the drive isn't encrypted, anyone who plugs it in can read it.
If your moved folders hold anything sensitive, encrypt the drive: in Finder, right-click it and choose Encrypt, or erase it as APFS (Encrypted) in Disk Utility. Storage Studio works the same with an encrypted drive once it's unlocked.