Just a thought that occurs. Is Brave launching some file at startup that the OS opens in Firefox? Might examining OS file associations be in order, to make sure either only Brave or only Firefox opens web-specific files?

Sorry, don't know how to test that in detail.

Hello TechHorse!

Thank you for the post!

I think I understand your line of thought.

Firstly, I have not chosen a "Standard browser" so whenever say a file or pop up generated by an app or a website needs to be opened, the OS asks with a list, which browser I would prefer.

But the OS sometimes randomly choses Firefox or Edge; like when I am opening a .HTML file of an exported bookmarks.

In this scenario Brave did not have any such “instances” in it for the OS to trigger launching, Firefox, FLOORP, Waterfox, and LibreWolf at the same time, as far as I remember. Also launching any of these launches each other.

But it is a valid scenario and I again thank you for your input.

As updating FLOORP, caused this issue and the other forks of Firefox reacted similarly, I labeled this scenario as browsers CRASHING, maybe there is a different term?!

» Does that mean no weird stuff happens when you launch Firefox in the new profile from the about:profiles page? «

Launching from Profile: Test2024, the window opened normally with previous session. I tried it a few times.

I uploaded a screenshot of shortcut properties for your ref.

Shortcut properties look normal, so there's obvious reason for the launch-fail-relaunch situation. Do you think Firefox might be trying to update itself at startup when that happens? Or maybe it is crashing for some non-obvious reason without an option to submit a crash report. You could check whether there is any information in the Windows Event Viewer, Applications log.

Weird stuff happened after I closed Firefox and launched again some time later, Firefox launched with new tab and I had to recover previous session.

This time tabs had crashed, see screenshot.

About: profile tab was running though and I launched Test2024, and that window opened with previous session running properly.

jscher2000, Thanking you for your time! Appreciate your help! Hope I am not keeping you awake.

I could not find any Firefox in Event Viewer, application.

Brave and Edge were there.

I rarely use Edge and since yesterday (13th) Brave is not installed, I only have Firefox and Vivaldi installed.

It's possible there is a problem in your regular profile if session restore never works automatically. I don't know what the problem is. If you don't get any good leads, one option is a Refresh. This will reset settings and remove add-ons: Refresh Firefox - reset add-ons and settings.

I can do the refresh and I have only Firefox container add on.

This Firefox is freshly installed on Monday (13th), I uninstalled and reinstalled.

Hello again TechHorse!

Your suggestion led me to consider things in a new perspective and as I mentioned earlier opening a .HTML bookmarks file without choosing, right click, open with, alternative, the OS chooses either Firefox or Edge. I think this behaviour plays some part in the issue which I experienced, as there were no such tabs open in Brave, but some tabs in Firefox could have generated although unlikely.

But I will remember this in future.

jscher2000, I have today uninstalled Firefox and Vivaldi, ran ipconfig /flushdns (I don’t know if that helps) and considering TechHorse suggestion, I found Firefox processes running even though Firefox was closed, closing processes in Task Manager and I also closed Windows Explorer processes and reinstalled.

After device restart I have installed Firefox and it seems to be running normally.

I will update tomorrow.

Have a nice day!

Finding firefox.exe in Windows Task Manager when Firefox is not running and not even installed can indicate a malware infection with its own "firefox.exe". In the future, I suggest switching to the "Details" tab of the Task Manager and adding the "Command Line" column to see what folder the mystery EXE is running from, and whether it has any unusual parameters (such as --headless, to run invisibly).

Thanks for the update!

All my browsers are running normally as yet.

I have learned a lot here, Thank you!

Could you please elaborate on;

» I suggest switching to the "Details" tab of the Task Manager and adding the "Command Line" column « I could add the command line in the “Processes” tab but cannot in the "Details" tab ( 🤨Windows for Dummies)

I couldn’t find any help on the web but I found this,

https://support.mozilla.org/en-US/questions/1291454

Could you please elaborate on; » I suggest switching to the "Details" tab of the Task Manager and adding the "Command Line" column « I could add the command line in the “Processes” tab but cannot in the "Details" tab ( 🤨Windows for Dummies)

I no longer have Windows 10, but it definitely should be available on the Details tab. Adding it to the Processes tab is fine, too, but you do have to expand the Firefox group to see it.

It seems not possible to add in Details tab. I do not like Win 11 so I am back here.

I did expand Firefox and went to file location before I posted here and all processes point to install location.

Anyways my browsers work normal now and I am inclined to believe those Firefox processes still running caused the mess.

Hello!

Today all my browsers behave normally and I hope it does so in future!

It seems likely that Firefox processes running when Firefox was closed, did provoke anomalies when FLOORP was updated.

It is interesting to note that all the Firefox forks installed were affected only Palemoon remained unaffected. Even Chromium based browsers were affected. TechHorse suggestion makes me think about OS and browsers and about browsers and browsers. Browsers do interface with each other to import\export bookmarks etc., they do “talk to each other”. I am no expert but I did experience “haywire ” the past few days and I lost data and time and energy.

I had Firefox as standard browser before and recently I was checking out different browsers.