I've been having some problems this week with my Home Server - every time I try to back up one of my machines it returns an error saying that a file is in use. I tracked this back to server error logs complaining of an IO error. Chkdsk returned nothing - but when trying to open the names file I got errors. So, it seems like a corrupted DAT file - problem is that these particular files are not mirrored or backed up. In the end I worked around it by removing the backup config for that machine, and then reinstalling the home connector software. A bit of a worry though if an old backup corrupts - there is no way I can see to recover it.