Thank you for reporting the bug and helping make Ubuntu even better. I suggest that you perform the following:
$ sudo apt-get clean
$ sudo apt-get update
Please verify you have no GPG errors after running 'apt-get update'. If you have no GPG errors, go ahead and run update-manager again and report back if you still have the problem.
Thank you for reporting the bug and helping make Ubuntu even better. I suggest that you perform the following:
$ sudo apt-get clean
$ sudo apt-get update
Please verify you have no GPG errors after running 'apt-get update'. If you have no GPG errors, go ahead and run update-manager again and report back if you still have the problem.