We're sorry to hear that your Firefox seems to be crashing when you open it. Please perform the following steps to give us a crash report ID that helps us find out more about the cause of the crash.

1. On the keyboard, press [Windows] The image "Windows key" does not exist. + [R]. This should bring up a Run window that contains a text field.
2. In that text field, type %APPDATA% and press Enter. An explorer window should open.
3. From that explorer window, double-click on the Mozilla folder, then double-click on Firefox and then on Crash reports. Double-click on submitted.
4. Now, you should see a list of files that contain reports. Go to View > Arrange Icons by > Modified to get the most recent files at the top of the window.
5. Open the most recent 5 files with a text editor and copy the IDs.
6. Paste each ID with bp- into the reply window on the forums.

Thanks in advance!

You can find more information and troubleshooting steps in the Troubleshoot Firefox crashes (closing or quitting unexpectedly) article.

Have you tried running Firefox in Safe Mode? https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode#w_how-to-start-firefox-in-4troubleshoot-modesf5safe-modesf

Also try windows in Safe Mode and see if you can open Firefox. Are you running the pro version of Win 11? What security software are you running?

We're sorry to hear that your Firefox seems to be crashing when you open it. Please perform the following steps to give us a crash report ID that helps us find out more about the cause of the crash.

1. On the keyboard, press [Windows] The image "Windows key" does not exist. + [R]. This should bring up a Run window that contains a text field.
2. In that text field, type %APPDATA% and press Enter. An explorer window should open.
3. From that explorer window, double-click on the Mozilla folder, then double-click on Firefox and then on Crash reports. Double-click on submitted.
4. Now, you should see a list of files that contain reports. Go to View > Arrange Icons by > Modified to get the most recent files at the top of the window.
5. Open the most recent 5 files with a text editor and copy the IDs.
6. Paste each ID with bp- into the reply window on the forums.

Thanks in advance! You can find more information and troubleshooting steps in the Troubleshoot Firefox crashes (closing or quitting unexpectedly) article.

Hi Paul,

there are a couple of crash reports in that folder but none with an ID of yesterday or today only older ones. But is was since yesterday that the problem appeared. It seams like the system doesn't recognize it as crash...

Now I found another folder that seems to contain crash reports: There is only one crash report and it has the current date.

Pls see the screenshot.

Have you tried running Firefox in Safe Mode? https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode#w_how-to-start-firefox-in-4troubleshoot-modesf5safe-modesf Also try windows in Safe Mode and see if you can open Firefox. Are you running the pro version of Win 11? What security software are you running?

Hello jonzn4SUSE,

I am running win 11 home. Just tried opening in troubleshoot mode. It worked i.e. it doesn't crash. Tab Session Manager is gone due to troubleshoot mode and the system doesn't "recognize" that it crashed so it doesn't show me the tabs of the last session with the option to restore it. I could restore the session by copy and pasting the session from 8th oct - see screenshot

security software: no extra software, I keep the windows security always up to date. I tried CCcleaner and an online virusscan today and it couldn't detect any malware or viruses.

Just closed firefox and opened again in normal mode. Same crash happens. Opening again in safe mode works fine...

jonzn4SUSE said

Have you tried running Firefox in Safe Mode? https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode#w_how-to-start-firefox-in-4troubleshoot-modesf5safe-modesf Also try windows in Safe Mode and see if you can open Firefox. Are you running the pro version of Win 11? What security software are you running?

Hello jonzn4SUSE,

I am running win 11 home. Just tried opening in troubleshoot mode. It worked i.e. it doesn't crash. Tab Session Manager is gone due to troubleshoot mode and the system doesn't "recognize" that it crashed so it doesn't show me the tabs of the last session with the option to restore it. I could restore the session by copy and pasting the session from 8th oct - see screenshot

security software: no extra software, I keep the windows security always up to date. I tried CCcleaner and an online virusscan today and it couldn't detect any malware or viruses.

Just closed firefox and opened again in normal mode. Same crash happens. Opening again in safe mode works fine...

Made some progress: Opened firefox with initial configuration without the add ons. Now it doesn't crash any more. Tried to restore the older session. Doesn't work. I followed these instructions: https://support.mozilla.org/en-US/kb/how-restore-browsing-session-backup

Firefox always the last session with 2-3 Tabs but I had way more open...

I copied upgrade.jsonlz4-20221010110315 and inserted it in the "sessionstore-backups" folder. Then I renamed it to "sessionstore.jsonlz4". FF still doesn't open that session. I even tried to rename it "previous" - doesn't work either.

The weird thing is that there is no "sessionstore.jsonlz4" to overwrite. Even when FF is closed there is no sessionstore file.

Just found the solution: The sessionstore.jsonlz was not in the "sessionstore-backups" folder but in the folder above. I did replace that file and the session was restored

Good work! Mark it as resolved.