Unfortunately, I'm not good at reading Windows error logs. If you are not getting the Mozilla crash reporter dialog (which captures data from Firefox's perspective), hopefully someone else can help with the event logs.

If you haven't shut down Windows and restarted it since this happened, please try that. Sometimes updated are queued to run at shutdown or startup, and until they complete, there may be inconsistent program or OS files.

If that doesn't help, you might consider rolling back to Firefox 53.0.3. You can set Firefox's update settings to ask you before updating, and then use the link in the Knowledgebase article to find the older version installer. I think the file format changes are minor to none, so running the old installer should work seamlessly with your existing settings. That said, it never hurts to make a backup of your profile folder just in case.

• Back up and restore information in Firefox profiles
• Install an older version of Firefox
• Advanced panel - Accessibility, browsing, network, updates, and other advanced settings in Firefox

Did a reboot: No difference.

Clicking the X in the upper right corner brought up the error box

An ALT/F4, the same.

Clicking Exit under File, the same.

As for trying to install the prior version, my druthers would be to just wait to see if others have this same prob since a fix might get released.

One thought of possible cause: I run Windows 8.1 Pro x64. Firefox here is 32 bit. But that has always been so....

Also wonder if upgrades are being tested on older Windows versions.

The crash is only when you exit Firefox or close one window in your Firefox session?

I don't know the respective populations of Windows versions in the Nightly and Beta test populations. I think Windows 7 may still be the largest subset, and then perhaps Windows 10, since Windows 8 and 8.1 users generally received a free upgrade.

Use one of these to close Firefox if you are currently doing that by clicking the close X on the Firefox title bar.

• "3-bar" menu button -> Exit (Power button)
• Windows: File -> Exit
• Mac: Firefox -> Quit Firefox
• Linux: File -> Quit

Boot the computer in Windows Safe mode with network support to see if that has effect in case security software is causing problems.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
• http://www.7tutorials.com/4-ways-boot-safe-mode-windows-10

Same problem on FF shutdown. (Win7 message: "FF stopped working". Started today.

Poss conflict w/ Malwarebytes (v3.1.2). If exit MBytes before closing FF, no problem. Sent email to MBytes support, but no response yet.

In reply to jscher2000, the problem happens when Firefox is closed. Any number of tabs (windows) can be closed with no problem, as long as one tab (window) remains open.

In reply to arclight, THANK YOU. You identified why FF is generating this error message every time it closes.

I run Spybot S & D, in addition to Norton AV. Closing Spybot before closing FF closes FF with NO error message. Did this multiple times. Re-activating Spybot, and then doing a close of FF, and I too get the same system error again.

I don't blame Spybot for this. Instead the problem is probably with FF. My reasoning: I have been running Spybot for many, many years. I have been running FF for maybe 2+ years. This "closing problem" appeared only after FF was upgraded. FF shows current version: 54.0 (32-bit).

Prior to latest FF upgrade, FF ran OK.

And, this same problem has now been identified in Windows 7, and Windows 8.1 Pro x64.

Following

Re User54: I agree. Seems to be latest FF update that created the problem. Problem can be avoided in MB by just deselecting Mozilla FF in its "Exploit Protection" (Settings-Protection Tab-Manage Protected Applications-Deselect Mozilla). Then MB can be running and FF can close normally. But that, of course, leaves you with less protection.

I note that the Internet Explorer browser was unaffected by the latest FF update and closes normally.   Points, as you said, the the latest FF update (v54).

Further info:

I installed the Tor Browser a few weeks before upgrading FF to version 54.

Tor Browser apparently uses a version of FF, for its own browsing sessions.

As far as I know, Tor keeps the FF version it uses in a separate directory.

I have used Tor multiple times since the upgrade of FF.

The point: Tor Browser, with its older version of FF, upon closing, does NOT produce the problem error message.

It is ONLY when running version 54 of FF that this error message appears.

Each day, it seems v54 presents additional problems. Now, cant log in to yahoo. No problem w/ IE. Too busy a schedule to take up troubleshooting as a 2nd career. If not fixed by tomorrow, will try Chrome. Sad. I've used FF for many years. (Apologies for the rant.) Best to all.

You can try these steps in case of issues with web pages:

You can reload web page(s) and bypass the cache to refresh possibly outdated or corrupted files.

• hold down the Shift key and left-click the Reload button
• press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
• press "Command + Shift + R" (Mac)

Clear the cache and remove the cookies from websites that cause problems via the "3-bar" Firefox menu button (Options/Preferences).

"Clear the cache":

• Firefox/Options/Preferences -> Advanced -> Network -> Cached Web Content: "Clear Now"

"Remove the cookies" from websites that cause problems.

• Firefox/Options/Preferences -> Privacy -> "Use custom settings for history" -> Cookies: "Show Cookies"

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Appearance
• do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

RE: Firefox 54.0.1 Upgrade.

Will it fix the ERROR introduced with the FF upgrade 54.0: "Firefox has stopped working" ERROR received every time FF is closed?

Seems to be a compatibility error while 'Spybot S & D' and other security programs run. (Prior to upgrade to FF 54.0 this ERROR problem was never an issue.)

Firefox 54.0.1 Release notes do not mention a repair for this.

Therefore reluctant to do another upgrade, which might do more damage.

ATT: Developers

The Upgrade to ver. 54.0.1 from ver. 54.0 did NOT fix the ERROR introduced in the upgrade to ver.54.0.

The error:

Upon EXIT (CLOSE of ALL tabs/windows in Firefox) Windows displays the Pop-Up message:

“Firefox has stopped working”

(Closing any number of Tabs/Windows does NOT cause the ERROR Message to be displayed, so long as at least ONE TAB/Window is open.)

This Pop-Up is NOT needed, since it confirms the user’s commands to EXIT/CLOSE Firefox.

AND it is an annoyance.

This Pop-Up ERROR MESSAGE was NEVER present, until upgrading to ver. 54.0.

It is NOT present in Internet Explorer, NOR is it present in Google Chrome.

Please fix.

THANK YOU.

Thank you for the additional detail. Do you use any security software that could be monitoring Firefox processes?

One of the main changes in Firefox 54 was to enable more individual content processes. In Firefox 48-53, the Firefox multiprocess feature would create one process for the UI and one process for content. Now Firefox will aim for four content processes. Perhaps this is a side effect of this change?

Could you test rolling back the number of content processes to 1? If this doesn't work, you may need to revert to single-process mode. Here's how you can try this:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful.

(2) In the search box above the list, type or paste ipc and pause while the list is filtered

(3) If the dom.ipc.processCount preference is bolded and "user set" to 4, double-click it and edit the value to 1, then click OK

Presumably that will not take effect until the next startup, at which time you should check it to make sure it hasn't reverted back. Any difference?

Alternately, you can disable multiprocess mode using a different preference:

(4) In the search box above the list, type or paste autos and pause while the list is filtered

(5) Double-click the browser.tabs.remote.autostart.2 preference to switch the value from true to false

Note: the exact name of the preference may vary, but it will start with browser.tabs.remote.autostart

At your next Firefox startup, it should run in the traditional way. Any difference?

I really do not understand all this.

I wrote the following, after running and closing FF many times, and NOT seeing the unwanted Windows Pop-Up ERROR Message.

My network became disconnected. Fixed that. Now the unwanted Windows Pop-Up ERROR Message is back. Every time I close FF.

I checked the changes in about:config, and they remain as changed.

Any suggestions?

Thank You! Thank You.

Yes, I use 2 security programs, Norton AntiVirus and Spybot S&D. Closing Spybot before running FF eliminated the problem. However, since Spybot, prior to FF ver. 54, was never an issue, and Spybot adds to PC security, it seemed reasonable to look to FF for a resolution.

After multiple modifications using “about:config” I wound up with the following changes that with NAV and Spybot running, the Windows’ Pop-Up ERROR Message no longer appears, when closing FF:

Under ipc:

dom.ipc.processCount value = 1

dom.ipc.processCount.extension value = 1

dom.ipc.processCount.webLargeAllocation value = 1

(The value of this entry was changed from a 10 to a 1)

Under autos:

browser.tabs.remote.autostart value = false

browser.tabs.remote.autostart.2 value = false

User54 said

Closing Spybot before running FF eliminated the problem. However, since Spybot, prior to FF ver. 54, was never an issue, and Spybot adds to PC security, it seemed reasonable to look to FF for a resolution.

I do think we've had other users mention problems with Spybot Search & Destroy "Immunization" feature in Firefox, but I thought that forcing Firefox back to using only one process was a good workaround for that.

I just don't see a lot of information on it. Perhaps try a Spybot forum like: https://forums.spybot.info/forumdisplay.php?4-Spybot

jscher2000 said

User54 said

Closing Spybot before running FF eliminated the problem. However, since Spybot, prior to FF ver. 54, was never an issue, and Spybot adds to PC security, it seemed reasonable to look to FF for a resolution.

I do think we've had other users mention problems with Spybot Search & Destroy "Immunization" feature in Firefox, but I thought that forcing Firefox back to using only one process was a good workaround for that.

I just don't see a lot of information on it. Perhaps try a Spybot forum like: https://forums.spybot.info/forumdisplay.php?4-Spybot

Since changes in “about:config” do not seem to have fixed this problem, I am wondering if the values should be changed back to their default values?

If so, please let me know the values to re-set.

Here is the listing of recent changes:

Under ipc:

dom.ipc.processCount value = 1

dom.ipc.processCount.extension value = 1

dom.ipc.processCount.webLargeAllocation value = 1

(The value of this entry was changed from a 10 to a 1)

Under autos:

browser.tabs.remote.autostart value = false

browser.tabs.remote.autostart.2 value = false

- - -

I do not believe the problem is generated by Spybot S&D.

1. An other post states that the exact same problem appears in FF using an other security program, and

2: This problem with FF did not exist until installing the ver.54 upgrade to FF.

- - -

More information that may identify what in FF is causing the Windows’ ERROR message to Pop-Up every time FF is CLOSED:

When this happens, (The Pop-Up is displayed) Windows’ Task Manager shows the following NEW Background Process:

Windows Problem Reporting (3... > Firefox

Requesting a Windows Dump File, resulted in creation of a new file, WerFault.DMP.

The Dump file is 87,348 KB, and is located:

C:\Users\hh\AppData\Local\Temp\WerFault.DMP

The DMP file is a combination of machine language and text.

Excerpting some text that may or may not identify the problem:

---> This program must be run under Win32 <---

An unexpected memory leak has occurred. The unexpected small block leaks are:

 bytes:     Unknown String  The sizes of unexpected leaked medium and large blocks are:     
 Unexpected Memory Leak

C : \ P r o g r a m F i l e s ( x 8 6 ) \ M o z i l l a F i r e f o x \ f i r e f o x . e x e

C : \ W I N D O W S \ s y s w o w 6 4 \ n t d l l . d l l w 6 4 . d l l

U s e r C a ll b a c k D i s p a t c h e r i U s e r C a l l b a c k D i s p a t c h e r

K E R N E L B A S E 

C : \ W I N D O W S \ S Y S T E M 3 2 \ K E R N E L B A S E . d l l

RSDSw k e r n e l b a s e . p d b

S t o p p e d w o r k i n g F i r e f o x C : \ P r o g r a m F i l e s ( x 8 6 ) \ M o z i l l a F i r e f o x \ f i r e f o x . e x e

C : \ P r o g r a m F i l e s ( x 8 6 ) \ M o z i l l a F i r e f o x \ f i r e f o x . e x e

C o l l e c t C r o s s P r o c e s s M o d u l e D u m p s f a i l e d

Out of memory. Cannot construct mod name signature. Cannot log ETW event, Error %d S t a c k H a s h 1 2 _

[and lots more]

And,

Just noticed, lots of firefox DMP files located:

C:\Users\hh\AppData\Local\CrashDumps\

All of these files are dated beginning July 9, 2017, when I started entering changes in “about:config”.

Hope some of this is helpful.

Addendum to above:

In C:\Users\hh\AppData\Local\CrashDumps\

There are NO DMP files with dates prior to July 9, 2017.

User54 said

Since changes in “about:config” do not seem to have fixed this problem, I am wondering if the values should be changed back to their default values?

You can do that by right-clicking each preferences and choosing Reset. The values sometimes are restored when you close and re-open the about:config screen, but in this case, they probably won't be restored until your next startup or the next one.

I cannot help you with dmp files.

ATT: Developers

This is a Summary of Windows ERROR using Firefox ver. 54.0.1

The Upgrade to ver. 54.0.1 from ver. 54.0 did NOT fix the ERROR introduced in the upgrade to ver.54.0.

The error:

Upon EXIT (CLOSE of ALL tabs/windows in Firefox) Windows displays the Pop-Up message:

“Firefox has stopped working”

(Closing any number of Tabs/Windows does NOT cause the ERROR Message to be displayed, so long as at least ONE TAB/Window is open.)

This Pop-Up is NOT needed, since it confirms the user’s commands to EXIT/CLOSE Firefox.

AND it is an annoyance.

This Pop-Up ERROR MESSAGE was NEVER present, until upgrading to ver. 54.0.

It is NOT present in Internet Explorer, NOR is it present in Google Chrome.

More information that may identify what in FF is causing the Windows’ ERROR message to Pop-Up every time FF is CLOSED:

When this happens, (The Pop-Up is displayed) Windows’ Task Manager shows the following NEW Background Process:

Windows Problem Reporting (3... > Firefox

Requesting a Windows Dump File, resulted in creation of a new file, WerFault.DMP

The DMP file is a combination of machine language and text.

Excerpting text from the Windows DMP file that may identify the problem:

>> “This program must be run under Win32" <<=

So the question: What program does FF call to close FF?

And, can it be changed to run under Windows Win32, or otherwise be fixed to run without causing the Windows ERROR Message Pop-Up ??

Please fix.

THANK YOU.

I too had FF failure to close. Using Win 7, FF 54.0.1 , Malwarebytes 3.1.2. Followed advice (above): "Problem can be avoided in MB by just deselecting Mozilla FF in its "Exploit Protection" (Settings-Protection Tab-Manage Protected Applications-Deselect Mozilla). Then MB can be running and FF can close normally." and PROBLEM SOLVED. But it's clearly a FF problem & I await a fix so that I can again SELECT Mozilla in MB. Arrrggggghhhh!