[PLUG] Strange update manager behavior

[Denis Heidtmann]

I ran the update manager.  It did not request a password, and it proceeded
to download over 200M of data.  It hung up about 80% of the way through the
install process.  I had to shut down to get out of the lock.  On restarting
I ran the update manager again.  It said that I needed to run a partial
upgrade as the previous upgrade did not complete.  When I started the
partial upgrade it seemed like it was going to upgrade, not just an update.
 (I am running Ubuntu 12.04 LTS, and do not want to upgrade 'till 3 years
from now.)  So I canceled it.  Next, I started the update manager again,
and it said my system was up-to-date.

In the auth log I see COMMAND=/usr/bin/update-manager --dist-upgrade.  I
did not enter that command.  I cannot decipher other logs.

Any clues as to what happened, what the damage might be, and what needs to
be changed to prevent a recurrence?

Thanks,
-Denis