The software-center no longer works. I don't know when it stopped working because I use it infrequently, but it was still working after upgrading to 23.04. Now I can't get anything out of it other than three blank tabs Explore, Installed, and Updates.
Clicking on Explore populates the screen with blank entry boxes, and nothing ever materializes in the boxes no matter how long you wait.
Clicking on Installed gives me a forever spinning gif and no results.
Clicking on Updates gives me a "Loading Updates... This could take a while" message, but it can run for hours without producing anything.
When I try to remove the app with sudo apt remove software-center it reports it can't remove it because it's not installed.
Yet, I have three entries under Settings->Apps that all take me to the same application, "Software Updater, Software & Updates, and Ubuntu Software."
Software Updater reports "Failed to download repository information."
Software & Updates appears to be a typical update configuration screen.
Ubuntu Software reports as described above with Explore, Installed, and Updates, and never provides anything from any of the three tabs.
The long and the short of it is I can't seem to install certain apps, like Vivaldi that rely on Ubuntu Software for installation.
This must be something simple, right?
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sudo apt update output
Hit:1 http://us.archive.ubuntu.com/ubuntu lunar InRelease
Hit:2 http://us.archive.ubuntu.com/ubuntu lunar-updates InRelease
Hit:3 https://paulcarroty.gitlab.io/vscodium-deb-rpm-repo/debs vscodium InRelease
Hit:4 http://us.archive.ubuntu.com/ubuntu lunar-backports InRelease
Hit:5 http://us.archive.ubuntu.com/ubuntu lunar-security InRelease
Hit:6 https://ppa.launchpadcontent.net/inkscape.dev/stable/ubuntu lunar InRelease
Ign:7 https://ppa.launchpadcontent.net/mscore-ubuntu/mscore-stable/ubuntu lunar InRelease
Err:8 https://ppa.launchpadcontent.net/mscore-ubuntu/mscore-stable/ubuntu lunar Release
404 Not Found [IP: 185.125.190.52 443]
Reading package lists... Done
E: The repository 'https://ppa.launchpadcontent.net/mscore-ubuntu/mscore-stable/ubuntu lunar Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
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Sorry for updating to the comment section.
I just wanted to say that I was able to reclaim the software-center by performing a restart following the removal procedure.
Well, almost. Under the Explore Tab selecting a category shows a screen of blank boxes, so the software-center still isn't performing correctly.
