Windows 10 reached EOS (end of support) on October 14, 2025. If you are on Windows 10, see this article.

Avatar for Username

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
Open

Firefox message

Firefox Launch failure
jbr replied
ihavahotrod
ihavahotrod

After the last update, Firefox won't open. Instead, I get this message:

"Firefox is already running but is not responding. The old Firefox process must be closed to open a new window."

I have closed it within the error message but the error message comes back each time I try to open Firefox.

Please help, Deb

After the last update, Firefox won't open. Instead, I get this message: "Firefox is already running but is not responding. The old Firefox process must be closed to open a new window." I have closed it within the error message but the error message comes back each time I try to open Firefox. Please help, Deb

All Replies (1)

jbr
jbr
  • Top 10 Contributor

Reboot the machine first.

If it doesn't start even after rebooting then get a fresh installer from firefox.com and run it over your current setup, it will get things up to date in case the update went wrong.

Ask a question

You must log in to your account to reply to posts. Please start a new question, if you do not have an account yet.