While configuring my computer to dual boot between XP and Vista, I created a “data” partition and moved stuff out of My Documents to the new partition. The plan was to easily see my data in either OS as well as have a clean, simple way to backup. I discovered that I didn't have permissions to the data files from within Vista (the data files were moved to the new partition while booted into XP). I tried taking ownership under Vista but was still restricted from doing so. KB article 308421 mentioned turning off simple file sharing in XP. I tried the same thing in Vista and voila - it worked.