I face the same problem when upgrading from karmic to lucid. The change proposed in comment #5 gets me going.
It needs a small modification though - the finally: clause is wrong: File "/usr/lib/python2.6/dist-packages/UpdateManager/Core/utils.py", line 113, in url_downloadable resp.close() -- version upgrade via update-manager or do-release-upgrade does not work with proxy authentication https://bugs.launchpad.net/bugs/479391 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs