FireFox won't launch

[THSearns]

I've removed and re-installed the latest FireFox ( 4.42.0.0) several times, attempted to change the user profile and nothing seems to make Firefox stable. It opens a window which very quickly breaks up into many smaller snippets which quickly disappear leaving me looking at my desktop. Most of the "fixes" for poor behaviour of FireFox involve doing something with links or buttons on that initial page, but I have no access to it.

There's clearly something wrong with the instructions for creating a New PRofile.

I think the problem is related to an "upgrade" from an earlier version of Firefox; the new one seems to fight with my Win 10 64bit O/S.

What do I do?

[DanRaisch]

That's not the latest version of Firefox. The current release version if 57.0.4. You might try uninstalling that old (2 years) version and installing the current. https://www.mozilla.org/en-US/firefox/

[THSearns]

That's not the latest version of Firefox. The current release version if 57.0.4. You might try uninstalling that old (2 years) version and installing the current. https://www.mozilla.org/en-US/firefox/

So I downloaded the version you suggested and attempted to install it. Eventually it crashed with an error "cannot find Firefox.exe." Also a second error message "this program won't run on this PC" , whatever that means. I think ther's a basic incompatibility with Win10 64 bit.

[DanRaisch]

There is no such incompatibility. I'm running that version of Firefox 64bit on a Win 10 box as I type this reply. Before that I had the 32 bit version of Firefox working well on the same system.

Close all applications and reboot the computer.
Delete any downloaded or partially downloaded Firefox installer files.
Clear the browser cache (of whatever browser you are using to download FF) and the Windows Temp directory.
Shutdown any anti-virus software you are running.
Download a new copy of the full installer from http://www.mozilla.org/en-US/firefox/all
Delete the directory C:\Program Files\Mozilla Firefox
Delete the directory C:\Users\YOURWINUSERID\AppData\Roaming\Mozilla where "YOURWINUSERID" is your specific Windows user ID
Run the installer.
Restart the anti-virus program.

[CaJazzman]

I, too, have the new Firefox Quantum installed and working perfectly, on Windows 10 Version 1709 X64. You must have something else that's causing these issues, and not Firefox.

[therube]

"cannot find Firefox.exe."

Are you using an old, existing desktop shortcut to FF or one that was newly created during the install of FF 57?