I had same issue. Try to reinstall with synaptic package manager these two packages : - update-manager - update-manager-core
Search for update manager, right click both packages, select Mark for Reinstallation and click Apply -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/954344 Title: update-manager crashed with ValueError in /usr/lib/python2.7/dist- packages/UpdateManager/UpdateManager.py: bad marshal data (unknown type code) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/update-manager/+bug/954344/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
