Following your suggestions I found and removed /etc/shadow.lock and /etc/passwd.lock - the problem is resolved. I can now install software correctly. Thank you very much for your help.
I remember some error reported at the end of the upgrade process about an incomplete upgrade and that certain packages might not work, but not from a guest session crash at that time. However I know that on this laptop the guest session always crashes when I try it, so maybe those files were left over from an earlier attempt to use guest session (they were dated Oct 2009). Thanks again for your valuable assistance. -- Update Manager requested a 'partial upgrade' - afterwards cannot add/remove software, causes 'dependency error' https://bugs.launchpad.net/bugs/577241 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
