When I try to do “Check for Updates” on Muon Package Manager I get an Authentication error. I can do a “Full Upgrade” and even get the authentication prompt when configuring “Sources”. However, no matter what I do I cannot just do a basic “Check for Updates”. I get no prompt and an rather an authentication error. On the web folks are saying it’s a kde-polkit issue? That QT and Lubuntu shares it or something?
Yes, this is the expected output. Unfortunately more digging is needed.
One cause could be, that there is already a apt/apt-get/dpkg process running, which is blocking (for good reasons) other processes. Therefore I suggest that you wait 1 hour and then retry to “Check for updates”.
If not, then we should dig in the logs (some commands require the key ‘q’ to exit). First reproduce the error, note the time and then check the logs: