I downloaded and installed Movie Manager 8 and ran it as administrator to authenticate it. The authentication worked and the program closed atomatically but when I re-opened it, it was not authenticated again! I only realized that after I'd added my 500+ collection and only very few were saved!
I am trying to fix these problems in windows 8... a solution can be run always xmm as administrator, this because windows block all things that XMM can do...
You can do this by go in the properties of the EXE file and set it permanently.