This is a valid bug and needs to be fixed. A nice error message should be sufficient rather than printing a stack trace.
My error log: pranith@labdesk:~/virtualbox/tmp/virtualbox-4.1.12-dfsg$ sudo add-apt-repository ppa:bobby-prani/virtualbox-precise You are about to add the following PPA to your system: More info: https://launchpad.net/~bobby-prani/+archive/virtualbox-precise Press [ENTER] to continue or ctrl-c to cancel adding it Exception in thread Thread-1: Traceback (most recent call last): File "/usr/lib/python2.7/threading.py", line 551, in __bootstrap_inner self.run() File "/usr/lib/python2.7/dist-packages/softwareproperties/ppa.py", line 99, in run self.add_ppa_signing_key(self.ppa_path) File "/usr/lib/python2.7/dist-packages/softwareproperties/ppa.py", line 127, in add_ppa_signing_key if len(signing_key_fingerprint) < 160/8: TypeError: object of type 'NoneType' has no len() ** Changed in: software-properties (Ubuntu) Status: Invalid => Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/968756 Title: apt-add-repository fails while adding ppa To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/software-properties/+bug/968756/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
