What version of Win O/S do you have installed? Did you completely uninstall any FF install and then go to the FF site to download just the x64 version?

https://download.mozilla.org/?product=firefox-latest-ssl&os=win64&lang=en-US

Also if you have a W10 there is no way to get both install let's say it's x64 O/S the version update will become x64 even if before it was x86 as it will remove the x86 and reinstall the x64 if done online update. And only way to get both x86 and x64 is if you did offline install of both to get both version but then again your system will beep at you stating one will cause error to the other. So My guess is you have older FF and the new FF is x64 and causing problem so you need to do some house cleaning there to resolve this issue.

I've tried that before... doesn't help. I've even tried removing all Mozilla directories from my system to help rectify to no luck.

Windows 7 64-bit Enterprise build 7601

Do this 1st please :

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

uninstall both versions of Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files and C:\Program Files(x86) Then restart system. Then run Windows Disk Cleanup. (Note: This should be Pinned and run Weekly, If never done below expect 10's of gig's) Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved. But you should make a back up before you do as per above URL's. Reinstall with Current Release Firefox 57.0.4 with a Full Version Installer

• https://www.mozilla.org/firefox/all/

Please let us know if this solved your issue or if need further assistance.

Do you have files in both locations?

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

With the update from 58.0 to 58.0.1 I have both again.... Yes, I have both 32-bit and 64-bit locations for Firefox. I used geekUninstall last time to uninstall all traces of both versions of firefox and that didn't work. I'm going to have to explore this a bit more; since it only happens when Firefox updates and not when I install.

Something doesn't add up here if you install x86 and then install x64 - the x64 will take over and the x86 will not work properly. Did you delete both folder and appdata/user folder as well? remove all traces off FF and use the link below and download only x64 and do custom install and see what is being installed til the end and then restart the computer and open FF and see what happens. Remember this will wipe clean all Addons and bookmark and history and anything associated in those folders. Scroll down to find your language version but only use the x64 version first assuming you have x64 O/S windows.

https://www.mozilla.org/en-US/firefox/all/

If it made sense I wouldn't be asking the question. I'm usually very resourceful at finding a solution or work-around myself. But, this one has me stumped.

1. I used geekUninstaller to uninstall all traces of Firefox... I even removed my profile last time deleting everything after getting a backup of my passwords and shortcuts.
2. I cleaned up everything I could in \ProgramData and the user directories for \Roaming \Local and \Localnow folders for Mozilla or Firefox.
3. geekUninstaller also removed any registry entries related that weren't removed.

I only install the x64 version of Firefox using the link you provided... I have to search for it all the time.... https://www.mozilla.org/en-US/firefox/all/ I was running Windows 7, but I've volunteered myself to update to Windows 10 recently. Only thing to add would be that I'm on an Enterprise domain.

Never use 3rd party uninstaller before using their own as in FF uninstaller before something else. Doing so you introduce more uninstall problems then your trying to fix and it could break something some but never tell you about it. Removing Registry is last resort as a FF uninstaller should've removed itself. So now you used geekuninstaller no one is going to be able to know what happened. Enterprise is only related to the O/S itself.

I've tried the Mozilla uninstaller several times..... same results. As soon as there is an update; it installs both x86 and x64 versions... even if I only install the x64 version.

geekUninstaller was just a last ditch effort to address the problem.

james.kosin said

I've tried the Mozilla uninstaller several times..... same results. As soon as there is an update; it installs both x86 and x64 versions... even if I only install the x64 version. geekUninstaller was just a last ditch effort to address the problem.

Something is definitely wrong here-I've never see that happen in all my days of using and installing FF. What your saying doesn't add up here.