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 40.3 will not start but older versions will

  • 5 replies
  • 2 have this problem
  • 234 views
  • Last reply by cor-el

more options

Firefox 40.0.3 will not start or open. I Uninstaller and put on 36.0.3 and it runs. Once I go to the About tab it automatically downloads the latest version. Then when I click on the Firefox icons nothing happens. I have repeated this process several times with the same results. XP Pro SP3

Chosen solution

Did you try Firefox Safe Mode with normal computer?

In that case, one of the other programs on your system is causing the problem. Look at the list of programs on your system. Anything look odd?

Windows: Start > Control Panel > Uninstall Programs. Mac: Open the "Applications" folder. Linux: Check your user manual.

Read this answer in context 👍 0

All Replies (5)

more options

Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac Options)
key, and then starting Firefox. Is the problem still there?


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

I rebooted windows in Safe Mode with networking, it started OK and was able to go to a few websites. What should I do next?

more options

Ok this worked, what do I do next?

more options

Chosen Solution

Did you try Firefox Safe Mode with normal computer?

In that case, one of the other programs on your system is causing the problem. Look at the list of programs on your system. Anything look odd?

Windows: Start > Control Panel > Uninstall Programs. Mac: Open the "Applications" folder. Linux: Check your user manual.

more options

It is possible that your firewall or other security software blocks or restricts Firefox or the plugin-container process without informing you, possibly after detecting changes (update) to the Firefox program.

Remove all rules for Firefox and the plugin-container from the permissions list in the firewall and let your firewall ask again for permission to get full, unrestricted, access to install for Firefox and the plugin-container process and the updater process.

See: