We're sorry to hear that Firefox is crashing. In order to assist you better, please follow the steps below to provide us crash IDs to help us learn more about your crash.

The crash report is several pages of data. We need the report numbers to see the whole report.

1. Enter about:crashes in the Firefox address bar and press Enter. A list of Submitted (and Unsubmitted, if any) Crash Reports will appear, similar to the one shown below.
2. Copy the 5 most recent Submitted Report IDs that start with bp- and then go back to your forum question and paste those IDs into the "Post a Reply" box.

Note: If a recent Report ID does not start with bp- click on it to submit the report.

(Please don't take a screenshot of your crashes, just copy and paste the IDs. The below image is just an example of what your Firefox screen should look like.)

Thank you for your help!

More information and further troubleshooting steps can be found in the Troubleshoot Firefox crashes (closing or quitting unexpectedly) article.

Thanks. All of these were this morning:

Report ID Date Submitted bp-7face418-5929-4c67-be7d-6cf260250915 15/09/2025, 19:14 bp-0769097b-b369-4c52-aa7e-85a0c0250915 15/09/2025, 19:14 bp-c45a6a7b-87ff-4aac-a623-239d80250915 15/09/2025, 19:14 bp-06393a7d-5ec2-45aa-abb2-967f70250915 15/09/2025, 19:14 bp-67bacfd3-befe-4153-9dd4-6c6df0250915 15/09/2025, 19:14 bp-0a66ff11-b2fb-46bc-aa93-233450250915 15/09/2025, 19:14 bp-988f7818-e718-4f1d-9d17-5df450250915 15/09/2025, 19:13

Okay. Let's try to go back in time before the crashing started. Post a screenshot of the files(in detailed view) from your sessionsstore-backups folder in profile folder. see screenshots

I'm not sure why you want this screenshot. I did manage in the end to get my windows back by copying previous.jsonlz4 to the folder above, then renaming it to sessionstore and then restarting Firefox. (This is a technique I figured out a few years ago that gives me back my windows and tabs from a while earlier, sometimes a day or more.)

You got it then. This is why I make a copy of the sessionstore-backups folder because sometime during a restart or update, the files in the folder have been reset in the past. Issue resolved?

Well, no. The question is whether someone can fix the bug that caused this. I did click on "View" for one of the bug reports and I noticed that in one place it says

MOZ_CRASH Reason (Sanitized) out of memory: 0x0000000000000080 bytes requested

Shouldn't a program be able to allocate memory without crashing?

A few minutes ago it crashed again. I looked at the bug report and this time it says

MOZ_CRASH Reason (Sanitized) [unhandlable oom] Failed to allocate new chunk during GC

I don't know what GC means, but again, why can't it allocate memory? Is there a bug in Windows?

I now have another problem -- I don't know whether it's related.

My History is empty. I'm not sure whether this happened at the same time as the crash I mentioned before. I see that I still have a file places.sqlite, which is quite large (102 Mb). I have another computer which is synced with this one, and there the history is still intact. (I have now cut the syncing in case the problem can spread!)

Today I Exited Firefox and restarted it, and the problem with History went away. Whew!

But it is another bug.

If restarting Firefox restores access to history/bookmarks, that often means the file was locked by another process at the last startup. It could be difficult to track down why that was the case.

Regarding out-of-memory crashes, my understanding is that Firefox requested a certain allocation (this usually is listed on the first panel in the crash report) and Windows declined to provide it. It certainly would be better if Firefox displayed a message that it had to unload some data, or run some kind of memory clean-up, etc., rather than crashing. I don't know how difficult that would be to do in the midst of whatever Firefox was trying to do at the time it got the OOM.

OK, thanks.