Hi everyone,

This will be a bit long because I'm going to include everything that I've tried to resolve this issue. Not certain, but this thread here may possibly be related to my problems as well since the system is running MX Linux 19.4
https://www.linuxquestions.org/quest...en-4175717142/

The MX System has several web browsers installed, two primary ones which are my standard go-tos ... Chromium and Firefox. Then there are also two backup web browsers that are used quite rarely, these consisting of Opera and Slimjet.

Yesterday the system went through a bunch of updates since I haven't updated the system for the past couple of months. Before the updates everything worked, was using Firefox just a day earlier. Since the updates everything but Firefox appears to work normally. The newest Firefox as part of the update process is Firefox version 107. When I click on the icon, the cursor spins for about 15 seconds, then the process ends without Firefox ever opening up on the screen.

1. Open the task-manager, find three from each other unrelated Firefox processes, end them all, reboot the system, start Firefox, same result ... just a spinning cursor and a bit later nothing.

2. Check the task manager, same three processes there as before. End them. Using the terminal to remove lock / parentlook to make sure it's not a previous faulty process. Reboot the system, yada yada yada, same result as before.

3. Did a delete of Firefox using remove with included --purge in the command in order to pretty much wipe out Firefox completely. Then rebooted the system, followed by opening up the MX package manager in order to install FF again. Install completed without a problem, did another reboot just for the heck of it. Attempted to start Firefox again, same result as before.

4. Also tried opening Firefox with the command line. This prompted zero actual results as far as the web browser opening on the screen, also no errors on the screen, but this time a bunch of almost identical looking errors within the terminal, right after attempting to initiate Firefox. These errors consist of dozens of lines (sorry, it's all on another machine). Those error lines all begin the same way:
(firefox:2050) Gtk-WARNING **:

Followed by (on the same line): 11:36:43:624: Theme parsing error: gtk-widgets.css:186:14: not a number.
Followed by an almost identical line which ends with ... expected a string.

Those two lines get repeated a couple of dozen times, each time beginning with (firefox:2050) Gtk_WARNING **:11:36:43:624:
The last three numbers change on the other lines, from the original "624" to 640, 651, 642, 348, 665, and so on. Seemingly random, but who knows?

All of the other web browsers continue to work as before. Strictly Firefox will no longer start up, no matter what I try. At that point I got on my primary machine where I have my forum access to this forum.
Any thoughts on this? Can the problem have something to do with the GTK errors?

Do you have any extensions or themes installed in Firefox? Have you followed the troubleshooting guide?

https://support.mozilla.org/en-US/kb...o-fix-problems

Also, this particular type of warning, when utilizing this search on the search engine .... terminal error message, gtk-warning **: .... generates tons of similar or related results, just not specifically with firefox. So apparently gtk does indeed have something to do with this issue as it also relates to numerous other familiar apps such as Gedit, Putty, and so on.

Thanks smallpond, but ...

I can't do anything which requires a firefox window since I can't get firefox started to begin with.

I won't make adjustments to any hardware settings since all other web browsers and apps such as libreoffice, gimp, and so on work correctly.

Whichever fix is implemented will have to be a straight shot through either the terminal or some generic settings within the XFCE settings menu which won't have an effect on any hardware. If all else fails I just won't use firefox on this machine anymore. It's just really puzzling / irritating since I've been using firefox for the past 15 years. This is the worst problem that I've come across. I've had to do complete re-installs before or find a missing file in order to correct issues, but never encountered anything like this.

UPDATE / GTK Errors:

Well, apparently I hadn't pulled in all of the required files which I'm using in two of the installed themes. Double-checked each of the two theme titles in Synaptic and pulled in a couple more GTK2 / GTK3 items that were related to those themes. After that all of the GTK related errors in the terminal were gone. Did an update check and some other minor stuff and everything appears to be correct now ... except for the fact that Firefox still won't open at all.

Does it work when you log into the computer as a different user?

Hmmmmm, I haven't tried that yet. Might give that a go tomorrow. Will let you know .....

Whoops, sorry about that. Allowed myself to get sidetracked.

I have another system, a laptop with pretty much the identical setup. After doing the last batch of updates which included Firefox, the same thing happened on that particular system. Chrome, Chromium, Opera, and Vivaldi all are working, but Firefox is not. Just a busy symbol for 10 seconds or so which then disappears without an error on the screen. Same thing when I try to use FF from within the Terminal. This has to be either directly related to Mozilla changes which took place in the past four weeks as well as something within the MX package manager, or perhaps it is some kind of a bug that's (hopefully) been eliminated with the latest version of MX 21.

The thing that pretty much floored me is the fact that Firefox was totally removed including --purge, followed by a shut down, a reboot, and then a new installation of FF. Yet something is still preventing FF from working on both of those systems. Everything else does work.
I did not try to create a new MX user because that would completely undermine the current desktop settings etc. from the existing user, thereby having to begin that aspect of it all over from scratch again. That's just too tedious and time consuming for me. Switching to another browser would be less cumbersome at that point.

I wonder if VPN can have something to do with that? I'm having MX linux and PIA VPN issues as well since a number of months. Perhaps utilizing an exterior VPN service conflicts with the new integrated privacy of Firefox? Been using MX for the past 4 or 5 years. Firefox was always my preferred choice and I have never had a problem with MX upgrades with Firefox compatibility before. Just very recently ....

Yes, but that's the point. I'm trying to work out if you've got some configuration file from the previous version which might be causing a conflict.

With Linux being a multi-user system, you can easily add another user account just to try this... and never use it again, or remove it if you want to.

Well, I can't be certain if the issues are the same / related or not, but I just installed the latest version of MX Linux (21.04 Wildflower) and within 48 hours the same issue began in that new Firefox. Lucky for me I decided to go ahead and use the sync option after having everything configured my way on the first day, so I was able to get everything but the open tabs back. Using "sync" is not really for me though since I use 4 different web browsers, each with their very own set of functions, three of which are specifically country related for three different countries.

I'm not sure what's going on with FF but from my point of view the profiles option is a nonsense and a waste of time. In this day and age of people using smartphones, tablets, and laptops / computers, I don't know a single person who shares their device with anyone else which would require multiple FF profiles. Been using computers for 31 years and never needed multiple profiles for myself either since I'm the only one on my devices. Personally, and speaking for what I believe to be the vast majority of FF users, I think adding FF profiles was just another way of generating problems and not solutions.

Case in point ... Mozilla / Thunderbird ...
Emails so much more important and sensitive than browser histories, especially if you're also using the Lightning Calendar & Planner extensively along with your email account management. Yet switching Thunderbird from one machine to another or one version of Linux to another is a total breeze, easy and quick as can be, while doing the same with FF now has me wondering if I shouldn't just use another browser such as Brave instead? KISS, keep it simple stupid. That really works best of all.
Ah well, it is what it is.

For what it's worth, Firefox 108.1 is now the current version available.
I run Firefox Release, Firefox Developer, and Firefox Nightly.

Not sure what's causing your specific issue, but making an educated guess, GTK2 / GTK3 may have something to do with it.

If you're willing to experiment some more, this may help:

Try installing a version directly from https://www.mozilla.org/en-US/firefox/new/
and place the resulting image (at least temporarily in a directory beneath your home directory; then you have 100% control over it, including the ability to get rid of it once you've determined whether one of their images will work or not.

Also: https://www.mozilla.org/en-US/firefox/channel/desktop/ allows you to choose to optionally try out one of the test browsers and see if they resolve any of the issues you've encountered.

Best wishes!

Thanks for all of the advice. The problem appears to have something to do with the profiles. Apparently some conditions can cause new profiles to be created which then becomes a problem when trying to access the original profile. I have been able to duplicate this issue on 3 different machines all of which received updated firefox versions. Somewhere between the updates, the reboots, and/or profile access there appears to be an issue that I can not understand. Been using FF for 15+ years daily on a variety of machines, never had problems until Mozilla began using Profiles & Synching. This should be a question asked right from the get-go during first use ... will you ever require more than one profile ... to which the user can answer "NO" if desired, to make sure that there is never more than one (the original) user profile.
Opera, Chrome, Chromium, Brave, Vivaldi, none of them cause this problem.
Switching to another computer or even OS with the same web browser should be a breeze in this day and age.
Sorry, venting ... thanks anyway.