It has been more than one week, and Firefox has started opening any downloaded file with VLC media player, even if I change the source of opening the file. In the next download, it will open again with VLC media player. What should I do?
I had the same problem and I resolved it like this:
--> Open the file
.local/share/applications/mimeapps.list with a text editor (
gedit for example).
--> If you have this line:
application/octet-stream=vlc.desktop; erase `vlc.desktop`
--> Save & restart computer
note: the "mimeapps.list" is now stored in /home/userprofil/.config/mimeapps.list in Ubuntu 18.04