A client of mine has standardized on Virtual PC 2007 for desktop virtual machine needs (not for their VDI or Server VMs, but just simple desktop VM needs). They recently created a transform for customizing the default install, but after deployment noticed that there was one major issue with the package. The issue is that VPC picks a subfolder of “My Documents” named “My Virtual Machines” as it’s default store location when creating a new virtual machine. This would obviously be a very bad choice when using Group Policy enforced managed folder redirection (just imagine how slow the VMs would be if they were stored on the network!, not to mention issues around home drive quotas, etc). Anyway, the packaging team couldn’t find an option in the app, nor a registry setting anywhere to change the default folder location for this. Also, since we’re dealing with a network location, you can’t get by with a subst command or junction point. While I didn’t know the answer myself, I figured Google might. After a quick search I came across a blog entry from Mr. Virtual PC Ben Armstrong. Ben states that the solution is to create a system environment variable named MYVIRTUALMACHINES and set it to a path on local disk. So as an example you could create a path named C:\VMs and then set MYVIRTUALMACHINES to C:\VMs. Thanks Ben!