Did you write this using that computer? or another?

Some problems occur when your Internet security program was set to trust the previous version of Firefox, but no longer recognizes your updated version as trusted. Now how to fix the problem: To allow Firefox to connect to the Internet again;

• Make sure your Internet security software is up-to-date (i.e. you are running the latest version).
• Remove Firefox from your program's list of trusted or recognized programs. For detailed instructions, see

Configure firewalls so that Firefox can access the Internet. {web link}

Start Firefox in Safe Mode {web link}

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

FredMcD said

Did you write this using that computer? or another? Some problems occur when your Internet security program was set to trust the previous version of Firefox, but no longer recognizes your updated version as trusted. Now how to fix the problem: To allow Firefox to connect to the Internet again;

• Make sure your Internet security software is up-to-date (i.e. you are running the latest version).
• Remove Firefox from your program's list of trusted or recognized programs. For detailed instructions, see

Configure firewalls so that Firefox can access the Internet. {web link}

I used the laptop to post this. It's my main PC that has the issue. I've removed Comodo from the main machine as that appeared in the original stack and the Comodo services looked like they were stuck.

I'm unable to do an safe mode start of firefox. If I hold down shift and click it doesn't run in safe mode. If I do the commandline for safe mode it still won't load fully.

I can see it running a child process with commands but it never fully opens. Only way I can kill the task is rebooting as even Process Explorer can't kill it.

Even PSKill can't kill it. Only a reboot works.

Something isn't right. After a reboot I ran it again. Only one process this time but some odd entries in the thread of Firefox.

I'm on

Firefox 68.0.1 - The lastest

Windows 7 Ultimate

Version 6.1 (Build 7601: Service Pack 1)

Try; TASKKILL /T /F /IM Firefox.exe

TASKKILL system [/U username [/P [password]]]

        { filter processid | /IM imagename } /T /F

Description:

   This tool is used to terminate tasks by process id (PID) or image name.

Parameter List:

   /S    system           Specifies the remote system to connect to.

   /U    [domain\]user    Specifies the user context under which the
                          command should execute.

   /P    [password]       Specifies the password for the given user
                          context. Prompts for input if omitted.

   /FI   filter           Applies a filter to select a set of tasks.
                          Allows "*" to be used. ex. imagename eq acme*

   /PID  processid        Specifies the PID of the process to be terminated.
                          Use TaskList to get the PID.

   /IM   imagename        Specifies the image name of the process
                          to be terminated. Wildcard '*' can be used
                          to specify all tasks or image names.

   /T                     Terminates the specified process and any
                          child processes which were started by it.

   /F                     Specifies to forcefully terminate the process(es).

   /?                     Displays this help message.

Filters:

   Filter Name   Valid Operators           Valid Value(s)
   -----------   ---------------           -------------------------
   STATUS        eq, ne                    RUNNING |
                                           NOT RESPONDING | UNKNOWN
   IMAGENAME     eq, ne                    Image name
   PID           eq, ne, gt, lt, ge, le    PID value
   SESSION       eq, ne, gt, lt, ge, le    Session number.
   CPUTIME       eq, ne, gt, lt, ge, le    CPU time in the format
                                           of hh:mm:ss.
                                           hh - hours,
                                           mm - minutes, ss - seconds
   MEMUSAGE      eq, ne, gt, lt, ge, le    Memory usage in KB
   USERNAME      eq, ne                    User name in [domain\]user
                                           format
   MODULES       eq, ne                    DLL name
   SERVICES      eq, ne                    Service name
   WINDOWTITLE   eq, ne                    Window title

   NOTE
   ----
   1) Wildcard '*' for /IM switch is accepted only when a filter is applied.
   2) Termination of remote processes will always be done forcefully (/F).
   3) "WINDOWTITLE" and "STATUS" filters are not considered when a remote
      machine is specified.

Examples:

   TASKKILL /IM notepad.exe
   TASKKILL /PID 1230 /PID 1241 /PID 1253 /T
   TASKKILL /F /IM cmd.exe /T 
   TASKKILL /F /FI "PID ge 1000" /FI "WINDOWTITLE ne untitle*"
   TASKKILL /F /FI "USERNAME eq NT AUTHORITY\SYSTEM" /IM notepad.exe
   TASKKILL /S system /U domain\username /FI "USERNAME ne NT*" /IM *
   TASKKILL /S system /U username /P password /FI "IMAGENAME eq note*"

Start your Computer in safe mode with network support. Then start Firefox. Try Secure websites. Is the problem still there?

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode Starting Any Computer In Safe Mode; Free Online Encyclopedia

This is the problem. You can't kill the task fully. Firefox still shows as running in process explorer and in tasklist and when you then view its threads. There is only one left and you can't view the stack of that thread.

I called for more help.

No Avast or AVG or Symantec Endpoint Security on that machine?

Firefox 68 introduces a new launch(er) process. This involves firefox.exe first detecting the privilege level and, for users with administrative privileges, launching the browser with standard user privileges (medium integrity process). The launcher also attempts to better insulate Firefox from unwanted DLL injections.

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

Not all security software likes this new process, and disabling UAC (setting it to never notify) also causes complications, especially on Windows 7.

Drag and Drop errors with Firefox Launcher Process enabled and Windows UAC disabled - How to Fix

Neither of those installed. Its look more likely and issue with Firefox 68. I've installed Firefox 67 and works fine. Then annoyingly, without asking updates itself to 68 and next run that fails to load. So it only appears to be happening with 68.

Hi whitingsteven, could you start Firefox with an additional command line switch to increase logging to the Windows Event Viewer.

That would involve updating the shortcut you use to start Firefox. Either:

• Right-click a Firefox desktop shortcut, then click Properties
• Right-click a Firefox icon pinned to the Taskbar then right-click Mozilla Firefox, then click Properties

Windows should show the Shortcut tab and select the Target field. The Target usually is along the following lines:

• "C:\Program Files\Mozilla Firefox\firefox.exe"
• "C:\Program Files (x86)\Mozilla Firefox\firefox.exe"

You would add a space and then the new switch, either:

• "C:\Program Files\Mozilla Firefox\firefox.exe" -log-launcher-error
• "C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -log-launcher-error

Ref. https://wiki.mozilla.org/Platform/Integration/InjectEject/Launcher_Process/#Other_Troubleshooting

Appears its crashing so badly that it's not even loading enough to leave any logs so above hasn't worked.

I don't know why that is happening.

Another user had a very stubborn non-killable Firefox process problem; you could review this thread and see whether anything there helps: https://support.mozilla.org/questions/1264441

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:
  https://www.bleepingcomputer.com/download/adwcleaner/
  https://www.softpedia.com/get/Antivirus/Removal-Tools/AdwCleaner.shtml
• SuperAntispyware:
  https://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:
  https://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

Scanned already and nothing related.

PC is out of action at the moment while I redecorate the room. However, I grabbed a copy of the reg before I turned it off and loading it into a VM to see if I get the same issue.