I had the same "cannot import name SIGNATURE_HMAC" error as papachan causing sso-login and thus also software-center on launch.
I resolved it by reinstalling the oauthlib package via pip. sudo pip install --upgrade oauthlib -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1085425 Title: Crash in software-center when starting service com.ubuntu.sso To manage notifications about this bug go to: https://bugs.launchpad.net/software-center/+bug/1085425/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
