Maybe a bit more info here: I have been using Firfox for the last decade and never had any issues. Yesterday, I got the update to v76.0.1 - afterwards, I cannot start Firefox anymore because it crashes at Startup. In safe mode, it crashes after 10 seconds. Clean-up does not work because the clean-up Programm crashes as well instantly. I did not Change anything on my Computer, all other programs work as usual. OS is Windows 10 Enterprise, no crash Reports are generated in the "C:\Users\xxx\AppData\Roaming\Mozilla\Firefox\Crash Reports" folder

If you can't get Firefox to open, you will have to do this the hard way.

https://support.mozilla.org/en-US/kb/mozillacrashreporter Open the file browser/explorer on your computer. Note: You may have to enable Show Hidden Folders / Files. Enter this in the address bar;

Windows: %APPDATA%\Mozilla\Firefox\Crash Reports\submitted Win 7/Vista: C:\Users\<username>\AppData\Roaming\Mozilla\Firefox\Crash Reports\submitted Win XP/2000: C:\Documents and Settings\<username>\Application Data\Mozilla\Firefox\Crash Reports\submitted

Mac OS: /Users/<username>/Library/Application Support/Firefox/Crash Reports/submitted Linux: /home/<username>/.mozilla/firefox/Crash Reports/submitted

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

Copy the most recent 5-7 File Names in the folder. Post the information in the reply box.

Sorry, but the Folder C:\Users\<username>\AppData\Roaming\Mozilla\Firefox\Crash Reports\submitted is empty on my Windows 10 machine. The parent Folder and C:\Users\<seweber>\AppData\Roaming\Mozilla\Firefox\Crash Reports\pending is full of files but Nothing from today or yesterday

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

That worked - I had to delete my profile and everything :-( How do I get back my bookmarks (I backed up my profile Folder …)?

EDIT: Nope, it didn't work - Firefox just crashed again. And again, there is no crash report ...

I called for more help.

Hi webersebastian, I think you are getting a crash dialog from Windows instead of the Mozilla Crash Reporter dialog. That would explain why you don't have any crash report files on disk under the Mozilla folder. But the Windows Event Viewer, Applications log might have more information about the crashes. This sometimes helps identify conflicting applications or drivers.

Here is the crash Event from syslog

Protokollname: Application Quelle: Application Error Datum: 18.05.2020 18:17:38 Ereignis-ID: 1000 Aufgabenkategorie:(100) Ebene: Fehler Schlüsselwörter:Klassisch Benutzer: Nicht zutreffend Beschreibung: Name der fehlerhaften Anwendung: firefox.exe, Version: 76.0.1.7432, Zeitstempel: 0x5eb403e6 Name des fehlerhaften Moduls: PayloadRestrictions.dll, Version: 10.0.17763.1, Zeitstempel: 0x7885c70a Ausnahmecode: 0xc0000409 Fehleroffset: 0x000000000003b614 ID des fehlerhaften Prozesses: 0x2dac Startzeit der fehlerhaften Anwendung: 0x01d62d2cfe11a745 Pfad der fehlerhaften Anwendung: C:\Program Files\Mozilla Firefox\firefox.exe Pfad des fehlerhaften Moduls: C:\WINDOWS\SYSTEM32\PayloadRestrictions.dll Berichtskennung: b526907a-29e2-4ad0-8509-b63543a4bddc Vollständiger Name des fehlerhaften Pakets: Anwendungs-ID, die relativ zum fehlerhaften Paket ist: Ereignis-XML:

<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">

 <System>
   <Provider Name="Application Error" />
   <EventID Qualifiers="0">1000</EventID>
   <Level>2</Level>
   <Task>100</Task>
   <Keywords>0x80000000000000</Keywords>
   <TimeCreated SystemTime="2020-05-18T16:17:38.392760700Z" />
   <EventRecordID>68264</EventRecordID>
   <Channel>Application</Channel>
   <Security />
 </System>
 <EventData>
   <Data>firefox.exe</Data>
   <Data>76.0.1.7432</Data>
   <Data>5eb403e6</Data>
   <Data>PayloadRestrictions.dll</Data>
   <Data>10.0.17763.1</Data>
   <Data>7885c70a</Data>
   <Data>c0000409</Data>
   <Data>000000000003b614</Data>
   <Data>2dac</Data>
   <Data>01d62d2cfe11a745</Data>
   <Data>C:\Program Files\Mozilla Firefox\firefox.exe</Data>
   <Data>C:\WINDOWS\SYSTEM32\PayloadRestrictions.dll</Data>
   <Data>b526907a-29e2-4ad0-8509-b63543a4bddc</Data>
   <Data>
   </Data>
   <Data>
   </Data>
 </EventData>

</Event>

Thank you! When I search for

C:\WINDOWS\SYSTEM32\PayloadRestrictions.dll

I did find threads about this. Example: https://superuser.com/questions/14512.../how-to-prevent-firefox-from-crashing-caused-by-payloadrestrictions-dll-error-on

According to a bug on file since Firefox 63(!), this may be caused by enabling "Export Address Filtering (EAF)" in the Exploit Protection feature in Windows Defender. I don't know whether there is any workaround other than turning off EAF. Another user posted these steps:

Windows Security control panel, go to App & browser control
Scroll down to the Exploit protection section, and click on Exploit protection settings
switch from the System settings to the Program settings tab
find firefox.exe among the programs to customize, Click to expand, then click Edit
scroll down to Export address filtering (EAF)
I just switched on "Audit only" and it stopped the crashes. I expect turning it off entirely would also help.

Thanks for the tip. Sadly, these settings can only be changed by a super admin and I don't have the right to change these settings on my computer. The issue only popped up after the upgrade to 76.0.1. Does that really mean, Firefox is not usable for me anymore? This looks to me like the closed bug 1483752 https://bugzilla.mozilla.org/show_bug.cgi?id=1483752 Should be opened again ...

The current bug is

https://bugzilla.mozilla.org/show_bug.cgi?id=1509748

I don't know why this wasn't an issue for you with previous versions of Firefox. Is this a managed environment where IT might have tweaked the Exploit Protection settings recently?

Yes, it is a managed envirmonment - but I have local admin priviledges and update Firefox myself. Your suggestions would be an incredible coincidence … that would mean, that the IT-Department activated exploit protection setting at exactly the same time that I updated Firefox to 76.0.1. Very unprobable … I think that this is rather a regression bug

I don't see much in the .1 release that looks very relevant --

https://www.mozilla.org/en-US/firefox/76.0.1/releasenotes/

-- but you could test using mozregression. The difference between working and not working is not very subtle, so it should go pretty quickly!

https://mozilla.github.io/mozregression/

Thanks for your support and time! Nice tool there mozregression. It looks like it might have been the IT Department after all ;-) Checking with mozregression, I found out that the first build not working is 2018-07-10. 2018-07-09 works ok. Any other ideas I could try to get Firefox working for me again?

That was a while ago. Perhaps that's when the Launcher Process (officially released in Firefox 68) first went into testing?

The Launcher Process is a feature designed to resist DLL injections, but when Firefox fights with Windows, Firefox loses, so possibly you'll need to find a way to disable it. I'm not sure of how to do that currently.

More info: https://wiki.mozilla.org/Platform/Integration/InjectEject/Launcher_Process/

This article https://www.ghacks.net/2019/01/21/firefox-will-block-dll-injections/ talks about a setting to enable or disable the Launcher Process. I would need to set browser.launcherProcess.enabled to "false". How can I do that without having to start Firefox?

Update: I edited prefs.js and set browser.launcherProcess.enabled to "false". However, Firefox still crashes - and the value is reverted to "true" in prefs.js after a crash :-( What can I do? Do I really need to use Chrome now? Thats the dark side ...

Sorry, the stuff that happens before the main Firefox process starts is like dark magic. You may want to offer you crash info in the existing bug and see whether they can provide a workaround.

Looks like I got the same issue here. I guess that it's most likely caused by a change by IT because I, too, am in a managed IT environment. Unfortunately, turning off EAF isn't possible due to IT mangement restrictions either.

I also tried to "Allow an app or feature through Windows Defender Firewall" explicitly for Firefox, but that also brought no change whatsoever.

The bug (https://bugzilla.mozilla.org/show_bug.cgi?id=1509748) suggests to me that it might work again on the Windows 1909 build - is that a valid interpretation?