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] + [R]. This should bring up a Run box 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.

There isn't a folder called submitted in crash reports (even though I have submitted them). There are folders called events, glean, and pending, a file I can't determine the type of named InstallTime20250529122813, and a .log document named submit.

InstallTime20250529122813 contains the following text only:

1749212441

The .log document only has the following:

[WARN crashreporter::net::ping] not sending legacy crash ping because no ping directory configured [WARN crashreporter::logic] not updating the events file; no events directory configured

Nothing I can find has an ID, unfortunately.

This is the info I get from details in the crash window:

BuildID: 20250529122813 CrashTime: 1749568636 InstallTime: 1749212441 ModuleSignatureInfo: {"Mozilla Corporation":["firefox.exe","mozglue.dll"],"Microsoft Corporation":["VCRUNTIME140.dll","msvcp140.dll"],"Microsoft Windows":["CRYPTBASE.dll","crypt32.dll","fltLib.dll","version.dll","bcrypt.dll","KERNELBASE.dll","ucrtbase.dll","bcryptPrimitives.dll","rpcrt4.dll","msvcrt.dll","sechost.dll","kernel32.dll","advapi32.dll","ntdll.dll"],"SentinelOne Inc.":["InProcessClient64.dll"]} ProductID: {ec8030f7-c20a-464f-9b0e-13a3a9e97384} ProductName: Firefox ReleaseChannel: release StartupTime: 1749568635 SubmittedFrom: Client Throttleable: 1 UptimeTS: 1.0 Vendor: Mozilla Version: 139.0.1 WindowsErrorReporting: 1 This report also contains technical information about the state of the application when it crashed.

Solved - this turned out to be SentinelOne after all.