SuperDuper and CommunigatePro

[mjj]

We are having an occasional problem with our CommunigatePro backups. What happens is that SD gets "stuck" while backing up an mbox file (not always the same account or same mbox) and incorrectly sees that mbox as being too big to backup. Our backup hd is larger than the source volume and we are using erase rather than smart update, so there should always be enough room for the clone to occur. When I check the log it tells me I've run out of space and looking at the contents of the backup hd shows that one the mbox files is over 100GB, even though it is actually only a few hundred MB's on the source volume.

It doesn't happen every time - most of the time the backup works fine. Any ideas as to what might be causing this?