Alright, I was able to figure out what the problem was. Apparently during that long stretch of not applying any updates, a new rolling distribution version of MX Linux was released. The new distribution version apparently included a change or two in the package management which then caused for the update manager not to work correctly anymore. I was able to duplicate the problem on two other machines, all of which had MX Linux 18 Live USB sticks that were used for the installation of MX Linux. Since then, MX 18.1 had been upgraded to MX 18.2 in the repos. With my older Live USB stick the error occurred on both machines. However, as soon as I did a ...
Code:
sudo apt-get dist-upgrade
followed by an immediate ...
Code:
sudo apt-get update
... on each machine, the problem disappeared.
I then created a new Live USB stick with the latest MX Linux, followed by testing that on the same two machines. Everything was fine of course, since everything was completely up to date right from the get-go. So no big deal, if this happens to you, just do a dist (version) upgrade and you should be fine. Perhaps this post will help someone else down the road.
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