Walnuts,
do you get this error on all the mailboxes or just a few...???
If it is on all the mailboxes, check the mailbox of the account you are using for Brick level backup.... it should not be hidden.
If it happens on a few mailboxes, check to see if those mailboxes have any corruption..
Cheers
Speshalyst So it Shall be Written!
So it Shall be Done!!