I have had a problem with two people in the past week so far to have this.
We have a Windows Server 2008 domain server and two of the people so far logging in has had their data disappear. I was able to recover their data but what happened was the profile still was there in the Documents and Settings, but it was not showing on the profile they were signed into. The weird part is, the profile they are signed into is their profile. It never created a user.domain profile folder and replaced the old "user" folder. It is still using the same folder, but not picking up the data that is in the desktop or my documents.
So far we have had this happen with two people. Has anyone ever seen this? I fear that the Active Directory may be becoming corrupt.