Okay, the Safe Mode is an important clue.

Did you try disabling Firefox from using hardware acceleration? If you make the change in Safe Mode it will be saved and apply when you try to start up in normal mode.

"3-bar" menu button (or Tools menu) > Options > Advanced

On the "General" mini-tab, uncheck the box for "Use hardware acceleration when available"

Any difference?

If that doesn't help, could you post a list of your extensions to see whether any is known to cause startup issues. To do that, you can copy/paste from the support information page. Either:

• "3-bar" menu button > "?" button > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

Scroll down until you find Extensions followed by a table. You can select and copy the entire table and paste into a reply. We understand that everything is disabled in Safe Mode, so we'll just have to assume they are all re-enabled in normal mode.

It doesnt change anything. still nothing.

list of extentions and their statuses:

Adobe Acrobat - Create PDF ## DISABLED Avast Online Security ## DISABLED Estonian ID Card Authentication Module ## DISABLED

FYI, the list of plugins is in extra info

In addition, i did a quick test. The safe mode NO LONGER starts up via regular method. now i have to shift+run as administrator to access safe mode.

Disable Avast as a test. It has caused problem in the past.

Tried doing things with avast disabled (the plugin was already disabled in non safe mode and regular mode) on the taskbar. Still absolutely nothing.

Start your Computer in safe mode with networking. Then start Firefox. Try Safe web sites. Is the problem still there?

Starting The Computer In Safe Mode;
Free Online Encyclopedia

I could be the Firefox window is opening outside your viewer.

You may have a corrupt xulstore.json file. https://support.mozilla.org/en-US/kb/changes-toolbars-and-window-sizes-are-not-saved

It does, infact, start when computer is in safe mode. no firefox safe mode or admin auth needed

firefox is NOT opening outside my screen area. When alt+tabbing through programs, firefox does not appear as a blank entry (which in case of your theory, it should).

i guess this is one step closer?

Estlib said

It does, infact, start when computer is in safe mode.

Then one of your other programs is at fault.

Disable your anti-virus type programs as a test. Then check other programs.

This thread sound similar, in that Firefox only displays a window with "run as administrator" or in Windows Safe Mode: https://support.mozilla.org/questions/1078663

FredMcD said

Estlib said

It does, infact, start when computer is in safe mode.

Then one of your other programs is at fault.

Disable your anti-virus type programs as a test. Then check other programs.

Antivirus disabled tests have already been done. It made no difference. The fact that firefox stopped working, is firefox's fault. It worked fine before. There is no reason to stop functioning now when the only thing that updated was firefox itself. Besides, i have so many programs, i dont know where to start.

jscher2000 said

This thread sound similar, in that Firefox only displays a window with "run as administrator" or in Windows Safe Mode: https://support.mozilla.org/questions/1078663

Checked it out - there was no solution. Since what his problem is, is pretty much what i have here, i suggest continuing with my question instead in hopes of finding an answer which might be the solution to both topics.

plans: locate the most recently updated programs between 12th and today to find out which one is the culprit. If thats the case...

Nothing found. I killed all unneeded tasks, and nothing.

Something interesting i forgot to mention. Once a broken process of firefox has been started, trying to open a safe mode or administrative process ontop of that will not work.

Estlib said

Once a broken process of firefox has been started, trying to open a safe mode or administrative process ontop of that will not work.

That seems normal. Usually Firefox will display an error at startup if it discovers firefox.exe in memory (and not let you proceed further).

There is no error. It never shows an error.

Try a clean reinstall and delete the Firefox program folder before (re)installing a fresh copy of the current Firefox release.

• Download the Firefox installer and save the file to the desktop
  https://www.mozilla.org/en-US/firefox/all/

If possible uninstall your current Firefox version to cleanup the Windows registry and settings in security software.

• Do NOT remove "personal data" when you uninstall your current Firefox version, because this will remove all profile folders and you lose personal data like bookmarks and passwords including data in profiles created by other Firefox versions.

Remove the Firefox program folder before installing that newly downloaded copy of the Firefox installer.

• (32 bit Windows) "C:\Program Files\Mozilla Firefox\"
• (64 bit Windows) "C:\Program Files (x86)\Mozilla Firefox\"

• It is important to delete the Firefox program folder to remove all the files and make sure that there are no problems with files that were leftover after uninstalling.
• http://kb.mozillazine.org/Uninstalling_Firefox

Your bookmarks and other personal data are stored in the Firefox profile folder and won't be affected by an uninstall and (re)install, but make sure NOT to remove personal data when you uninstall Firefox as that will remove all Firefox profile folders and you lose your personal data.

• http://kb.mozillazine.org/Profile_folder_-_Firefox
• http://kb.mozillazine.org/Profile_backup

• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Clean_reinstall

Hey there, question owner of https://support.mozilla.org/questions/1078663 here.

jscher2000 suggested installing the ESR version of Firefox (see other thread) and it did solve my issue. Even if it is only a temporary workaround, it might be worth testing it to solve your issue...

The "delete-folder-before-reinstall" worked, thanks guys.