This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Firefox won't start, also unable to activate safe mode

  • 3 iimpendulo
  • 2 inale ngxaki
  • 3 views
  • Impendulo yokugqibela ngu FredMcD

more options

Firefox was working fine until I restarted my PC today (which runs Windows 7 Ultimate), and now it won't open no matter how many times I click the taskbar icon or the Start Menu/desktop shortcut.

One popular fix I noticed while troubleshooting is to reset Firefox by holding shift while opening the program, then selecting the "reset" option. Holding shift while I try to open it does nothing.

I tried restarting my PC multiple times, and tried starting it up in Safe Mode with Networking. I've also uninstalled and reinstalled Firefox twice. Same problem.

Any suggestions? Thank you.

Firefox was working fine until I restarted my PC today (which runs Windows 7 Ultimate), and now it won't open no matter how many times I click the taskbar icon or the Start Menu/desktop shortcut. One popular fix I noticed while troubleshooting is to reset Firefox by holding shift while opening the program, then selecting the "reset" option. Holding shift while I try to open it does nothing. I tried restarting my PC multiple times, and tried starting it up in Safe Mode with Networking. I've also uninstalled and reinstalled Firefox twice. Same problem. Any suggestions? Thank you.

All Replies (3)

more options

Start your Computer in safe mode with networking. Then start Firefox. Try Safe web sites. Is the problem still there?

Starting The Computer In Safe Mode;
Free Online Encyclopedia

more options

FredMcD said

Start your Computer in safe mode with networking. Then start Firefox. Try Safe web sites. Is the problem still there? Starting The Computer In Safe Mode;
Free Online Encyclopedia

Yes, when I started my PC in Safe Mode with Networking, the same problem occurred.

Running the Windows troubleshooter tells me that Firefox is an "incompatible application."

Ilungisiwe ngu RayAP9

more options

Shut down Firefox. Using your file browser, open the Programs Folder on your computer.

Windows: C:\Program Files C:\Program Files (x86)

Right click on Firefox.exe and select Properties. Now select Compatibility. Turn Off Run This Program In Compatibility Mode, and Run This Program As An Administrator.

Do the same for any Firefox shortcuts you have. Now restart Firefox.