Windows 7 Home Premium 64bit Previous install of Firefox problematic - profile manager wouldn't show. Removed installation. Downloaded / installed 80.0.1 (64bit). Same problem. Can start Firefox normally but cannot start/interact with profile manager (firefox.exe -p) Try to open profile manager. Window doesn't appear. Firefox is running in task manager. No option to show window. Kill process. Try to start profile manager again. Same thing. Window doesn't appear but Firefox process in task manager. Restart machine several times. Still doesn't work. Enter 'about:profiles' in firefox address bar. Create new profile. "Launch profile in new browser". New browser does not appear but exists as process in task manager. Shut down first firefox window (the one used to create new profile). Kill windowless process in task manager. Run 'firefox.exe -p' in Run. Window doesn't appear (as before). Kill process in task manager. Run firefox from shortcut. Opens in new profile. Problem: want and need to run Profile Manager.