Publisher saving files as tmp files

Hi EE

I have an issue that I cant figure out why.
Domain users when saving publisher files to their home drives on win7 machines find that their publisher file they have worked on changed the pub extension to tmp when they log back in again. As a result they are not able to open their file again.

This is happening on a random basis which I cant seemed to figure out. Has anyone come across this before as why publisher would save a file as tmp extensions. This is happening for office 2010 on win 7 pro/ent machines.

Thanks