Firefox won't launch on Windows 10

Question

I am using Windows 10.0.19042.906 Professional x64, and suddenly Firefox won't work anymore.

Double clicking on Firefox shortcut on desktop and "C:\Program Files\Mozilla Firefox\firefox.exe" have no effect, for a second there is a rolling ring near the cursor, indicating Firefox is loading, then nothing happens, no windows has showed up and no error messages, no crash dumps, just nothing, there is no Firefox process in taskmgr.exe and procexp.exe, so Firefox isn't suspended.

I am using Firefox 88.0 x64 and this thing is 100.00% reproducible, I have Googled this and found solutions I have already tried and failed to solve this problem.

I have uninstalled Firefox and removed %appdata%\Mozilla\Firefox folder and restarted Windows and reinstalled Firefox and this problem persisted.

I have tried "C:\Program Files\Mozilla Firefox\firefox.exe" -safe-mode and it doesn't work.

So how can I actually run Firefox again?

Answer 1

I have just solved the problem and I don't even understand how it worked, but I had solved it.

The step I took was very simple, I just renamed the "Mozilla Firefox" folder located at "C:\Program Files" to simply Firefox, and then I am able to launch Firefox.

I have confirmed if I rename the installation folder back to "Mozilla Firefox" the program won't launch, the behavior is completely reproducible.

I used the default online installer and it installs Firefox to the default location, I think just renaming the installation folder might cause other bugs so I downloaded the offline installer and reinstalled Firefox to "C:\Program Files\Firefox".

This solves the problem.