Firefox will not start unless I specify --display=:0.0


Several weeks ago Firefox stopped opening when I try running it using normal methods (Super → “firefox” → ENTER).

FF will only start if I specify a display when executing from the terminal:

firefox --display=:0.0

If I open FF any other way, no window will display, however a new process does appear to run. It used to be “Firefox” but as of yesterday, it is now just "GeckoMain"

Additional details

If I click on a web link somewhere in the OS (GNOME Terminal > Menu > About > Website, for example) I get the following:

$ firefox --full-version
Mozilla Firefox 93.0 20211005175701 20211005175701

$ echo $DISPLAY

$ which firefox

$ cat /usr/bin/firefox
exec /usr/lib/firefox/firefox "$@"


I’ve tried:

Is the display specified on command line different from the one in $DISPLAY?


$ echo $DISPLAY

Any info as to why the browser engine is now the process name?

I can’t really say as to why. I don’t know what happened that made it do that. Some update perhaps?

Update: If I choose “Gnome classic” at the login screen, Firefox launches like normal. However it still appears as “GeckoMain” in System Monitor.