SUMMARY I had an awkward kdenlive package installation error. I had the same problem in the past but I forgot the workaround that worked. So I completed uninstalled (purged) kdenlive and began using appimage instead. The command "sudo dpkg --configure -a" displays nothing. However, I keep getting this error message from Discover upon login: Offline Updates Failed to update 1 package Error while installing package: trying to overwrite '/usr/share/icons/breeze-dark/actions/16/add-subtitle.svg', which is also in package breeze-icon-theme 4 STEPS TO REPRODUCE 1. Preferably use kdenlive ppa to update or to install it to make sure that this wierd "conflict" with breeze-icon-theme package occurs. 2. Then completely uninstall/purge kdenlive. 3. Reboot. SOFTWARE/OS VERSIONS Operating System: KDE neon 5.22 KDE Plasma Version: 5.22.4 KDE Frameworks Version: 5.84.0 Qt Version: 5.15.3
UPDATE: The message is gone after a fresh offline update is completed with success. Probably this means there's a minor bug somewhere which causes Discover to fail refreshing te status of package installations.
The error message is in fact telling you the real error. :) This is caused by a packaging problem in your distro or with the PPA publisher. You need to contact them about it.
Yes, I know that there's an error in the kdenlive package(s) concerned, and I did report it. However, I'm trying to point out here that Discover might also be falsely reporting this error *even after kdenlive has been wiped out from my system*. The fact that this message disappeared (without any change affecting the status of purged and uninstalled kdenlive package) after the next round of offline updates might be confirming my suspicion. Although a very minor one, this might still be a Discover bug, an error in checking/refreshing current the status of packages, and/or reporting it in that way.
If that's the case, then it would be a bug in PackageKit, which is where this error message comes from. Discover is simply reporting it to you. It can't know whether the error is real or not. :)