How far does Firefox get into startup? I'm not sure whether "UptimeTS: 8.00534" indicates 8 seconds.

Will Firefox start normally in its Troubleshoot Mode? In that mode, Firefox temporarily deactivates extensions, hardware acceleration, any userChrome.css/userContent.css files, and some other advanced features to help you assess whether these are causing the problem.

When Firefox is not running:

Hold down the Shift key when starting Firefox. (On Mac, hold down the option/alt key instead of the Shift key.) A small dialog should appear. Click the Open button.

Note: Don't use the Refresh without first reviewing this article to understand what will be deleted: Refresh Firefox - reset add-ons and settings.

Any improvement?

Ref. Diagnose Firefox issues using Troubleshoot Mode

I don't know whether there is a way to extract more technical crash details from the file you're working with (I'm used to reading crash reports online where everything is clearly labeled...). Hopefully someone else can advise on that.

this is what i get when i try to start it in Troubleshoot Mode

Thank you for reporting back. Do you recall any unusual events prior to Firefox not being able to run?

Do you want to try re-running a full installer, in case the program files are damaged? Here's the process I recommend:

(1) Download a fresh installer from

https://www.mozilla.org/firefox/all/desktop-release/

(2) Close Firefox and open Windows File Explorer and find this folder:

C:\Program Files\

(3) Right-click Mozilla Firefox and rename to OldFirefox

(Note: if Mozilla Firefox is not here, try looking in C:\Program Files (x86)\)

(4) Run the installer. It should detect and use your existing profile folder.

Any improvement?

i followed the above steps. same issue. it only started happening with V140. and all our machines have the same issue. older versions work fine but when they auto update to V140, Firefox starts crashing.

This could be the issue in bug 1973947, which is heading toward blocking two older DLLs implicated in various crash signatures:

• ff64.dll, versions 1.0.0.1 and earlier, published by Jiangsu Agile Technology Co., Ltd (http://www.agile-china.com/en/).
• nsccor0364.dll, versions 2024.5.7.380 and earlier, which appears to be part of Samsung SDS NASCA / Endpoint Security-Document.

Do those publishers/products sound like something you're running and, if so, does updating the products help with the crashes?

Does your additional crash report data list either of those DLLs?

not sure what you mean by additional crash report data. where can i find that information. here is another crash report:

AdapterDeviceID: 0x682c AdapterDriverVersion: 21.19.141.0 AdapterSubsysID: 2b1e1028 AdapterVendorID: 0x1002 AvailablePageFile: 16960552960 AvailablePhysicalMemory: 7990259712 AvailableVirtualMemory: 138531398516736 BackgroundTaskMode: 0 BuildID: 20250616215311 CPUMicrocodeVersion: 0x64 CrashTime: 1750868218 DOMFissionEnabled: 1 DOMIPCEnabled: 1 HeadlessMode: 0 InstallTime: 1750788070 LastStartupWasCrash: 1 ModuleSignatureInfo: {"Mozilla Corporation":["firefox.exe","xul.dll","gkcodecs.dll","nss3.dll","mozglue.dll","lgpllibs.dll"],"Microsoft Windows Software Compatibility Publisher":["msvcp140.dll","VCRUNTIME140_1.dll","VCRUNTIME140.dll"],"Microsoft Windows":["twinapi.dll","MpDetours.dll","NapiNSP.dll","nlansp_c.dll","wsock32.dll","winrnr.dll","dbgcore.dll","directmanipulation.dll","Windows.UI.Immersive.dll","Windows.UI.dll","textinputframework.dll","ktmw32.dll","twinapi.appcore.dll","wshbth.dll","npmproxy.dll","dhcpcsvc.dll","dhcpcsvc6.dll","winmm.dll","version.dll","propsys.dll","CoreUIComponents.dll","netprofm.dll","winnsi.dll","DWrite.dll","CoreMessaging.dll","wtsapi32.dll","uxtheme.dll","DXCore.dll","directxdatabasehelper.dll","dxgi.dll","dwmapi.dll","dbghelp.dll","windows.storage.dll","IPHLPAPI.DLL","dnsapi.dll","kernel.appcore.dll","ntmarta.dll","mswsock.dll","CRYPTBASE.dll","msasn1.dll","winsta.dll","ntasn1.dll","ncrypt.dll","cfgmgr32.dll","devobj.dll","bcrypt.dll","profapi.dll","ucrtbase.dll","crypt32.dll","msvcp_win.dll","win32u.dll","KERNELBASE.dll","gdi32full.dll","WinTypes.dll","bcryptPrimitives.dll","wintrust.dll","shell32.dll","shlwapi.dll","user32.dll","rpcrt4.dll","clbcatq.dll","SHCore.dll","setupapi.dll","ole32.dll","psapi.dll","kernel32.dll","advapi32.dll","imm32.dll","nsi.dll","oleaut32.dll","msvcrt.dll","gdi32.dll","ws2_32.dll","combase.dll","msctf.dll","sechost.dll","ntdll.dll"]} Notes: FP(D10-L1000-W0000100-T01) Has dual GPUs. GPU #2: AdapterVendorID2: 0x8086, AdapterDeviceID2: 0x4c8a, AdapterSubsysID2: 2b1e1028, AdapterDriverVersion2: 32.0.101.6556DWrite? DWrite+ WR? WR+ ProductID: {ec8030f7-c20a-464f-9b0e-13a3a9e97384} ProductName: Firefox ReleaseChannel: release SafeMode: 0 SecondsSinceLastCrash: 347 StartupCacheValid: 0 StartupCrash: 1 StartupTime: 1750868218 SubmittedFrom: Client SystemMemoryUsePercentage: 76 Throttleable: 1 TotalPageFile: 65870069760 TotalPhysicalMemory: 34067255296 TotalVirtualMemory: 140737488224256 UptimeTS: 6.28103 Vendor: Mozilla Version: 140.0 This report also contains technical information about the state of the application when it crashed.

I was referring to the last part: "This report also contains technical information about the state of the application when it crashed."

Is that from the Windows Event Viewer?

When the Mozilla Crash Reporter is able to capture crash data, it lists the modules called in each thread, and this should include third party DLLs called during loading. However, that is recorded in an unreadable file and only becomes readable after submission to the crash report server.

• Unsubmitted reports: %APPDATA%\Mozilla\Firefox\Crash Reports\pending
• Submitted reports: %APPDATA%\Mozilla\Firefox\Crash Reports\submitted (these files contain a useful ID starting with bp we can use to find them on https://crash-stats.mozilla.org/)

no, i got the information from the Firefox Crash reporter. see attached picture event viewer doesn't have much attached. picture also attached. i do not see the submitted folder. i only see the pending folder

the submit.log file has the following information [ERROR crashreporter] exiting with error: The application failed to generate crash information.

I can't think of any other way to research the problem DLL(s). Hopefully more info on the timing of a Firefox 140.0.1 update will become available soon.

version 140.0.1 was released but we are still having the same issue

AdapterDeviceID: 0x682c AdapterDriverVersion: 21.19.141.0 AdapterSubsysID: 2b1e1028 AdapterVendorID: 0x1002 AvailablePageFile: 17074872320 AvailablePhysicalMemory: 7119880192 AvailableVirtualMemory: 138531376406528 BackgroundTaskMode: 0 BuildID: 20250625213854 CPUMicrocodeVersion: 0x64 CrashTime: 1750953181 DOMFissionEnabled: 1 DOMIPCEnabled: 1 HeadlessMode: 0 InstallTime: 1750952723 LastStartupWasCrash: 1 ModuleSignatureInfo: {"Mozilla Corporation":["firefox.exe","xul.dll","gkcodecs.dll","nss3.dll","mozglue.dll","lgpllibs.dll"],"Microsoft Windows Software Compatibility Publisher":["msvcp140.dll","VCRUNTIME140_1.dll","VCRUNTIME140.dll"],"Microsoft Windows":["twinapi.dll","MpDetours.dll","NapiNSP.dll","nlansp_c.dll","wsock32.dll","winrnr.dll","dbgcore.dll","directmanipulation.dll","Windows.UI.Immersive.dll","Windows.UI.dll","textinputframework.dll","ktmw32.dll","twinapi.appcore.dll","wshbth.dll","npmproxy.dll","dhcpcsvc.dll","dhcpcsvc6.dll","winmm.dll","version.dll","propsys.dll","CoreUIComponents.dll","netprofm.dll","winnsi.dll","DWrite.dll","CoreMessaging.dll","wtsapi32.dll","uxtheme.dll","DXCore.dll","directxdatabasehelper.dll","dxgi.dll","dwmapi.dll","dbghelp.dll","windows.storage.dll","IPHLPAPI.DLL","dnsapi.dll","kernel.appcore.dll","ntmarta.dll","mswsock.dll","CRYPTBASE.dll","msasn1.dll","winsta.dll","ntasn1.dll","ncrypt.dll","cfgmgr32.dll","devobj.dll","bcrypt.dll","profapi.dll","ucrtbase.dll","crypt32.dll","msvcp_win.dll","win32u.dll","KERNELBASE.dll","gdi32full.dll","WinTypes.dll","bcryptPrimitives.dll","wintrust.dll","shell32.dll","shlwapi.dll","user32.dll","rpcrt4.dll","clbcatq.dll","SHCore.dll","setupapi.dll","ole32.dll","psapi.dll","kernel32.dll","advapi32.dll","imm32.dll","nsi.dll","oleaut32.dll","msvcrt.dll","gdi32.dll","ws2_32.dll","combase.dll","msctf.dll","sechost.dll","ntdll.dll"]} Notes: FP(D10-L1000-W0000100-T01) Has dual GPUs. GPU #2: AdapterVendorID2: 0x8086, AdapterDeviceID2: 0x4c8a, AdapterSubsysID2: 2b1e1028, AdapterDriverVersion2: 32.0.101.6556DWrite? DWrite+ WR? WR+ ProductID: {ec8030f7-c20a-464f-9b0e-13a3a9e97384} ProductName: Firefox ReleaseChannel: release SafeMode: 0 SecondsSinceLastCrash: 44 ShutdownReason: AppRestart StartupCacheValid: 0 StartupCrash: 1 StartupTime: 1750953181 SubmittedFrom: Client SystemMemoryUsePercentage: 79 Throttleable: 1 TotalPageFile: 65870069760 TotalPhysicalMemory: 34067255296 TotalVirtualMemory: 140737488224256 UptimeTS: 7.18 Vendor: Mozilla Version: 140.0.1 This report also contains technical information about the state of the application when it crashed.

anyone tried a new profile?

Yes, apparently Firefox 140.0.1 is not a universal solution. You can add your experience to the feedback thread at https://old.reddit.com/r/firefox/comments/1ll0rps/firefox_14001_released_with_hopefully_fix_to/

Meanwhile, whatever is causing this problem appears to be too widespread to be brand new malware, but far from universal. One user reported seeing anti-malware active in Windows Task Manager when Firefox was starting/failing. Perhaps there was an updated program DLL or a new detection signature, but it also could have been a coincidence.

Whatever it is, it appears to target Firefox specifically because numerous users reported being able to work around it by renaming firefox.exe to something different, such as edge.exe or firefox1.exe.

I haven't seen a definitive new bug filing, but they can be hard to find and interpret.

renaming firefox.exe to firefox1.exe worked for me

If you now go into the about:crashes screen, are you able to submit reports for yesterday's crashes?

yes. see attached

https://crash-stats.mozilla.org/report/index/e4fa459b-6f83-487a-914f-a4c350250626#frames

Thanks! As you may have noticed from the Bugzilla tab on the report, there is an active bug for this crash signature: https://bugzilla.mozilla.org/show_bug.cgi?id=1974259

They replicated the problem by adding application-specific Exploit Protection settings for firefox.exe -- in particular, "Validate Handle Usage" => "Override System Settings" => On (screenshot: https://bug1974259.bmoattachments.org/attachment.cgi?id=9497094)

I don't know whether that is relevant to your environment, or it's just one way to discover that Firefox's error handling needed improvement. If you did that that setting, it would explain why the crash is filename-sensitive, since application-specific Exploit Protection is linked to specific executable file names.