Hello, I have the latest version (140) of Firefox installed on a Windows 11 laptop with the latest Windows updates. It works fine for my user (who, BTW, has admin privileges) but it won't even start for my wife's Windows user. To be precise, "won't start" means that when you try to launch it it sometimes looks like it's trying to create a window but immediately closes it with no error messages, no crash reports, no logs, nothing at all. It won't even start from the Run menu with any command line flag like -p, -ProfileManager or even -safe-mode, I tried all of them. Other things I've tried: 1) Check the Windows event logs. Nothing. 2) Run sfc /scannow to check for corrupt system files. 3) Uninstall Firefox, delete the Program Files\Mozilla Firefox folder, and re-install it. 4) Move the entire Firefox folder inside %appdata% to a temporary folder outside users. Firefox recreates it, creates 2 new profiles and dies silently again! 5) ...and a lot of other things that I read online and do not remember anymore. At this point I'm at a loss and I'm an IT guy. Of course I have no idea how this happened, the browser used to work fine up until a week ago or so. Other software that might interfere is Malwarebytes, but it works fine for my user, so... 🤷🏻‍♂️ Thanks in advance for any ideas.