Just to clarify, I believe the MCR_CACHE_ROOT is defined on the compiling computer and does not need to be defined on the target computer. Perhaps if you do that it will unpack stuff to that constant folder every time instead of some different temporary folders in the \Documents and settings/user/whateverCrazyTemporaryFolder. I actually set my environment variable to dot for other reasons and so haven't fully investigated if the unpacked stuff goes to different folders on every run. I do know that if you compile a *new* version though, it will go into a different folder because it has new and different stuff to unpack. If you set MCR_CACHE_ROOT = . then at least these folders will be subfolders of the folder where your exe lives rather than some weird hidden folder under Documents and Settings. I've probably totally confused Arda :-( I'm sorry that they make it so confusing but that's the way it is.