I can't copy all the contents of the doc I found here somewhere but this might be helpful---I don't know if it still applies or not. It's pretty old so it might be obsolete---
"Microsoft's new consumer operating system brought many changes related to security and game integration. Both these areas affect game development in WME. This chapter will guide you through all the possible problems and new WME's abilities related to Windows Vista.
Game development WME tools and the engine itself work fine in Windows Vista. There's one possible problem you should be aware of, though. In Windows Vista even if the user has administrative privileges, under normal circumstances the rights are lowered to normal user. This means the user doesn't have write access to the "Program Files" directory. For this reason, do NOT store your WME project folder in Program Files.
When creating a new project in ProjectMan, the project is created in the "Documents" folder by default, which is fine. Unfortunately older versions of WME defaulted to Program Files. Therefore, if your project is in still stored Program Files, and you are intending to upgrade to Windows Vista, please move the entire project folder elsewhere (preferably to your Documents folder), otherwise ProjectMan might fail to compile the game."
---and then goes on to talk about save games.