we have a clustered nss volume sles10sp4+oes2sp3 (latest patches).

Our Windows 7 clients have massive problems with Office 2010 doc files that are reported to be in use by another user but really aren't.
There are many solutions to this problem.

One thing we found out is that, some users have different sessions, listed by ncpcon connection list, at the same time holding some open files. But they are definitely just logged in once.

a) How can we prevent this?

Also strange is that even after the user shutdown his pc, the ncp connection was still listed, using command from above.
Why is that the case?