How to Rename Virtual Disk files

I ran into an issue while evaluating esXpress, a utility for imaging virtual machines (excellent program, check it out!). It looks like early versions of ESX 3.0 created identical virtual disk file names if the virtual machine used multiple datastores. This causes some snapshot operations to fail which is an issue with esXpress as it uses snapshots during the backup process. This problem has been fixed in later versions of ESX.

The solution was found in this VMWare document which gives the details on how to rename the virtual disk files.