How to fix unresolvable file conflict errors upgrading or installing software RPMs

I install updates on a pretty regular basis and — most of the time — they install without a problem. By updates I mean installation of patches and new features for installed software, but not a Fedora release upgrade.

A recent update of the VLC media player on my Fedora workstation failed with the error shown below.

Running transaction
Transaction failed: Rpm transaction failed.

- file /usr/lib64/vlc/plugins/codec/libfaad_plugin.so conflicts between attempted installs of vlc-plugins-freeworld-3.0.21-4.fc42.x86_64 and vlc-plugins-base-1:3.0.21-24.fc42.x86_64  

Although this error occurred when updating VLC, I’ve occasionally encountered similar errors with other software as well. I tried the usual circumventions such as adding --allowerasing and --skip-broken to the command, but that didn’t work in this case. I also removed VLC and tried to reinstall it, but that also failed with the same error.

What did work was the following command to clean out all the downloaded cache and metadata used by DNF.

# dnf clean all

Everything worked as it should and VLC is now updated and working as it should. So, if you’re having file conflicts during an upgrade or update, be sure to use this command to delete all repository cache and metadata.