Apparently there's a bug that crept into a recent update release for Access. Yeah, it happens. If you have problems opening a database that's shared on a network, this is why.

They already have a fix, and all you have to do is update Access... again. Read more about it here:

• Error in Access when opening a database on a network
• How to revert to an earlier version of Office
• What version of Office am I using?

Mike Wolfe gives additional details and instructions in his excellent blog:

• Access Bug Alert

This illustrates another reason why it's good to keep backups, not only of your database files, but of your system configurations as well. I try to make a backup system image of my drives at least every couple of months. If you've got a mission critical machine, especially, try to do this monthly.