You'll have strange problems trying to backup active Virtual Machines.

Microsoft's Virtual Server 2005 (and other versions) don't work well with Backup Exec.  If you attempt to backup a *.vhd file, the VM session will crash, and you'll have an unusable backup.  Backup Exec's log, however, will say that everything's fine.

In short, don't try to backup *.vhd files that are in use.  To backup a VM, do one of the following:

- Stop the VM, run the backup, then start the VM

- Stop the VM, copy the *.vhd file elsewhere, start the VM, then backup the copy you just made

This applies to all version of Backup Exec and all versions of Microsoft Virtual Server.