I currently dual boot ubuntu studio and ubuntu ultimate gamers edition.
both are maverick

I first encountered this error when i booted into ubuntu ultimate and did a routine update manager, update.
I used sudo fsck on the ubuntu studio partition and it did the trick.
I got back to the grub boot screen and ubuntu studio was all systems go.

I figured it was a problem with the update and probably a one time thing.
well today I booted into UE again and there was no update, but when i restarted I can back to the same error screen "unknown filesystem grub rescue" prompt.

any help is appreciated, thanks