We had big problems with a particular release of our workstation antivirus dvp software.
On Logoff the dvp would hold a lock on the NTUSER.DAT and NTUSER.LOG files meaning that they could not be copied back to the server.
If a user then logged back on the the same workstation, the roaming NTUSER.DAT could not be copied back to the workstation, as the most recent copy was still locked.
A reboot between logons got around the problem (not very good I know).
The issue has since been fixed in a subsequent release of our DVP – although we could have got around it by excluding NTUSER.DAT and .LOG files from being scanned.
If the problem is repeatable – I’d suggest turning off DVP and see if this fixed it. If so – compare your versions against workstations without the problem.
Size of roaming profile also had an effect.
We now redirect the MyDoc’s etc to a location under the users home directory.
We also prohibit the saving of anything other than shortcuts to the desktop.