Every so often I back up my VMware Fusion virtual PC to an external hard disk.
After my VM crashed and refused to boot up copying the backup seemed the easiest fix.
Problem
After 20 minutes of copying the Windows VM would fail to copy as some files were in use.
Solution
make sure the vm is shutdown (not running or suspended) and turn off your time machine.
The VM file is a package right click and show contents, then delete the contents of the ‘Applications’ folder.
You should now be able to copy to the VM off the external to your local disk.