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

Lolu chungechunge lwabekwa kunqolobane. Uyacelwa ubuze umbuzo omusha uma udinga usizo.

Lost previous Firefox, cannot load replacement

  • 1 baphendule
  • 1 inale nkinga
  • 16 views
  • Igcine ukuphendulwa ngu James

more options

I am using mac OS X 10.11.6. I will not be updating my OS X because newer OS X versions are incompatible with applications I use for my job.

I went to your site offering the latest version of Firefox. While going thru the download process, it asked if I wanted to replace my previous version, so I selected 'yes'.

After continuing, I received an alert saying this version was not compatible with my OS X. I went back to download my older version and cannot find it available anywhere. So now I have no Firefox. Where can I obtain the last version supported by mac OS X 10.11.6?

I am using mac OS X 10.11.6. I will not be updating my OS X because newer OS X versions are incompatible with applications I use for my job. I went to your site offering the latest version of Firefox. While going thru the download process, it asked if I wanted to replace my previous version, so I selected 'yes'. After continuing, I received an alert saying this version was not compatible with my OS X. I went back to download my older version and cannot find it available anywhere. So now I have no Firefox. Where can I obtain the last version supported by mac OS X 10.11.6?

All Replies (1)

more options

Firefox ever since 79.0 and later has required macOS 10.12 (ten.twelve) at minimum to run.

https://support.mozilla.org/en-US/kb/firefox-mac-osx-users-esr

The most current you can run on the old EOL macOS 10.9, 10.10, 10.11 is Fx 78.15.0 ESR released back on October 5, 2021.

https://archive.mozilla.org/pub/firefox/releases/78.15.0esr/mac/en-US/ for other locals see https://archive.mozilla.org/pub/firefox/releases/78.15.0esr/mac/