Firefox Won’t Open On Windows 7 Ultimate 64-Bit, Firefox Won’t Launch In Safe Mode
I use multiple browsers on a daily basis either because some sites work better in some browsers versus others or to test web applications, etc. Typically I prefer Chrome over any other browser but sometimes I use Firefox because of some of the plugins available. Sometime in the past the Firefox installation on my Windows 7 Ultimate 64-bit laptop became corrupted so when I attempted to launch Firefox it would flash for a moment in the taskbar and then close immediately. The Firefox window would never display on the screen or even attempt to display on the screen however you could see the process for a moment in the Windows Task Manager as shown in the below image.
Firefox Process Displayed For A Moment In Task Manager:
After a bit of troubleshooting I found the easiest way to resolve the problem was to download the latest Mozilla Firefox browser installer from the mozilla.com site by clicking here and run the installer. Instead of installing the new version it will actually upgrade your old version as shown in the below images of the Firefox Setup process.
Mozilla Firefox Setup: Upgrade Current Firefox Installation
Mozilla Firefox Setup: Upgrade Process
After running the installer, which technically upgraded the current Firefox installation, Firefox was able to run without issue. I am assuming that Firefox must have been corrupted during the last upgrade for some reason or another.