[dnanian]

It's not so much that it'd be "open", but OSX does some strange things when you log into a FileVault account to "fool" the system into thinking your files are local. Basically, they mount a special volume and then "link" it to your home folder.

The special volume is stored on the drive, but in this linked situation, it's in an "open" configuration, rather than "closed" (like when you log out).

So, to get it to be as it would be when you reboot -- the safest configuration -- it's best to log out and into a non-FV account. This closes the volume and puts its away, ensuring that the backup proceeds as if your computer was turned off. That way, when you boot from the backup, it's as if you had started from a power-off situation, rather than from logged-in.

FUS isn't enough, unfortunately, because the volume isn't closed.