FileVault 2 and the Guest User account
One of the interesting things about working with FileVault 2 is that things are still appearing as new functionality. One thing that’s appeared as of 10.7.2 is that FileVault is sometimes enabling a guest user at the pre-boot login screen.
When you log in as that guest user, you don’t get access to your hard drive. In fact, the only thing you get access to is Safari and a network connection. Why is it here? Also, why does it appear on some encrypted machines and not others?
Long story short, in my opinion, the Guest User account is a trap for anyone stealing your machine. The Guest User account appears when you do two things:
• Sign into iCloud on that Mac.
• Enable Find My Mac.
If you don’t sign in with iCloud and then enable Find My Mac from that machine, you don’t get that guest user login at the FileVault pre-boot login screen. If you have enabled it, Find My Mac phones home with the Mac’s location almost immediately when you log in with the Guest User account.