This a wayland security feature, not working with pkexec, which synaptic (and other app) is using. This will be worked on later, with the next 18.04 release.
The actual workaround is the open an x session, instead of a wayland one (ubuntu default), or follow the thread explanation below: https://ubuntuforums.org/showthread.php?t=2373238 ** Changed in: synaptic (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1721544 Title: I installed "Synaptic Package Manager", but I can not start it. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/synaptic/+bug/1721544/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
