How long is Firefox running when it crashes? What were you and the browser doing at the time? watching clips, reading, just surfing . . . .

Several times it crashed while I was typing (either into some form field on a website or the search box in the uppper right corner - I'm using a classic theme).

But I think sometimes it even crashed while I was just moving the mouse etc., there is no clear pattern.

That's why it would be nice to get a crash log. I'm a developer myself.

Is Firefox completely closing without showing the Mozilla Crash Reporter dialog? Do you get the Windows crash dialog, or no dialog at all?

Yes, it completely closes. No Crash Reporter dialog. No Windows crash dialog, nothing. Really weird.

Were those real crashes (i.e Firefox closed and needed to be restarted) or was this a Tab crash ?

If it was a Firefox crash then also check the Windows Event log.

I had missed your last reply a few minutes ago, but you can still check the event log.

Found a couple of these in the event log (rather few hang messages, but some):

Faulting application name: firefox.exe, version: 67.0.0.7075, time stamp: 0x5cdded92 Faulting module name: ntdll.dll, version: 10.0.18362.113, time stamp: 0x3817fba9 Exception code: 0xc0000005 Fault offset: 0x000000000004d5bc Faulting process id: 0x4cd4 Faulting application start time: 0x01d51a4194b2e253 Faulting application path: C:\Program Files\Mozilla Firefox\firefox.exe Faulting module path: C:\WINDOWS\SYSTEM32\ntdll.dll Report Id: 89f75d05-4ed3-4347-8d6f-05f8d8e010bd Faulting package full name: Faulting package-relative application ID:

Faulting application name: firefox.exe, version: 67.0.0.7075, time stamp: 0x5cdded92 Faulting module name: ntdll.dll, version: 10.0.18362.113, time stamp: 0x3817fba9 Exception code: 0xc0000005 Fault offset: 0x0000000000039432 Faulting process id: 0x40ac Faulting application start time: 0x01d5193848e65104 Faulting application path: C:\Program Files\Mozilla Firefox\firefox.exe Faulting module path: C:\WINDOWS\SYSTEM32\ntdll.dll Report Id: 4a622185-2e84-45f3-9b85-8b8ac63b5933 Faulting package full name: Faulting package-relative application ID:

The program firefox.exe version 67.0.0.7075 stopped interacting with Windows and was closed. To see if more information about the problem is available, check the problem history in the Security and Maintenance control panel.

Process ID: 2028
Start Time: 01d51982868a3cee
Termination Time: 4294967295
Application Path: C:\Program Files\Mozilla Firefox\firefox.exe
Report Id: 95915b84-33e3-4635-97eb-90ac01c7d5d1
Faulting package full name: 
Faulting package-relative application ID: 
Hang type: Top level window is idle

Faulting application name: bad_module_info, version: 0.0.0.0, time stamp: 0x00000000 Faulting module name: unknown, version: 0.0.0.0, time stamp: 0x00000000 Exception code: 0xc0000005 Fault offset: 0x00007ffb540384c0 Faulting process id: 0x3f34 Faulting application start time: 0x01d51986a2f3d73a Faulting application path: bad_module_info Faulting module path: unknown Report Id: 7fcf9335-1e9f-4b7b-9e4c-db21b2646dfc Faulting package full name: Faulting package-relative application ID:

ntdll.dll = Microsoft Perform a System File Check to fix corrupted system files

Win 7, 8, 10, Vista: https://support.microsoft.com/en-us/kb/929833 Win XP: https://answers.microsoft.com/en-us/windows/forum/all/windows-xp-scan-and-fix-disk-errors/6fe2827a-4be6-4bc1-8083-5139b5aa3a3d

Wiki - Windows 10 System File Check http://answers.microsoft.com/en-us/windows/wiki/windows_10-update/system-file-check-sfc-scan-and-repair-system-files/bc609315-da1f-4775-812c-695b60477a93

Type about:preferences#advanced<enter> in the address bar. Select Data Choices. Turn on Enable Crash Reporter.

Note: For Firefox v56+ its; about:preferences#privacy Under Firefox Data Collection turn on Allow Firefox To Send Crash Reports.

Restart Firefox.

Forgot to mention, I think this started happening after the latest Windows 10 update. It was a major update, took several hours to complete and it changed system sounds etc.

So I'm confident the file isn't corrupted (as it was probably updated), but maybe there's an incompatibility somewhere?

Try this at some point; Let’s do a full clean re-install;

Note: Firefox comes in three or more folders on all computers. They are;

Maintenance: (Programs Folder) <Windows Only> Firefox itself: (Programs Folder) And two folders in the profile of each user on the computer for each Firefox profile for that user.

If you remove the Firefox folder, the user profiles would not be affected.

Download Firefox For All languages And Systems {web link}

Save the file. Then Close Firefox.

Using your file browser, open the Programs Folder on your computer.

Windows: C:\Program Files C:\Program Files (x86) Note: Check Both Folders

Mac: Open the "Applications" folder. https://support.mozilla.org/en-US/kb/how-download-and-install-firefox-mac

Linux: Check your user manual. If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it. See Install Firefox on Linux; https://support.mozilla.org/en-US/kb/install-firefox-linux

If you downloaded and installed the binary package from the Firefox download page, simply remove the folder Firefox in your home directory. http://www.mozilla.org/firefox#desktop ++++++++++++++++++++++++++++ Look for, and remove any Mozilla or Firefox program folders. Do not remove the Mozilla Thunderbird folder if there is one.

Do Not remove any profile folders.

After rebooting the computer, run a registry scanner if you have one. Then run the installer. +++++++++++++++++++++++++++ If there is a problem, start your Computer in safe mode and try again.

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode This shows how to Start all Computers in Safe Mode; Free Online Encyclopedia

And it crashed again, right after I had opened a new tab:

Faulting application name: bad_module_info, version: 0.0.0.0, time stamp: 0x00000000 Faulting module name: unknown, version: 0.0.0.0, time stamp: 0x00000000 Exception code: 0xc0000005 Fault offset: 0x00007ffb5400d5bc Faulting process id: 0x28fc Faulting application start time: 0x01d51abcafee94de Faulting application path: bad_module_info Faulting module path: unknown Report Id: dfa0144f-db93-4ba2-8bc0-d0fca61dd083 Faulting package full name: Faulting package-relative application ID:

Maybe do a malware check with several malware scanning programs on the Windows computer.

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware

Please scan with all programs because each program detects different malware. All these programs have free versions.

Make sure you update each program to get the latest version of their databases before doing a scan.

• Malwarebytes' Anti-Malware:
  https://www.malwarebytes.com/
• AdwCleaner:
  http://www.bleepingcomputer.com/download/adwcleaner/
  http://www.softpedia.com/get/Antivirus/Removal-Tools/AdwCleaner.shtml
• SuperAntispyware:
  http://www.superantispyware.com/
• Microsoft Safety Scanner:
  https://www.microsoft.com/security/scanner/en-us/default.aspx
• Windows Defender:
  https://windows.microsoft.com/en-us/windows/using-defender
• Spybot Search & Destroy:
  http://www.safer-networking.org/en/index.html
• Kasperky Free Security Scan:
  https://www.kaspersky.com/security-scan

You can also do a check for a rootkit infection with TDSSKiller.

• Anti-rootkit utility TDSSKiller:
  https://support.kaspersky.com/viruses/disinfection/5350

https://support.kaspersky.com/viruses/utility

No, that's not what I want. I just want a proper log file.

I have disabled hardware acceleration now, let's see if it helps.