During my daily work with Ubuntu it sometimes happens that shutdown process is very slow. It takes about 10 minutes. But this happens only after about 3-4 hours of continuous work. (If I shutdown right after ubuntu start the shutdown is normal). What can be the reason? How can I see detailed information what is going on during shut down?
syslog file contains a little information and I cannot see what causes such delay.
Also sometimes Ubuntu suddenly logs me out. This also happens after 3-4 hrs of work. I think there is a relation between these two issues.
Update. I think that it is slow because some process cannot be stopped/killed. If so, how can I determine which process?
This is the shutdown screen:
("Killing all remaining processes" fails)