Where did you install Firefox from? Help Mozilla uncover 3rd party websites that offer problematic Firefox installation by taking part in our campaign. There will be swag, and you'll be featured in our blog if you manage to report at least 10 valid reports!

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

Èròjà atẹ̀lélànà yii ni a ti fi pamọ́ fọ́jọ́ pípẹ́. Jọ̀wọ́ béèrè ìbéèrè titun bí o bá nílò ìrànwọ́.

I have downloaded the new Firefox 4 on Mac OS X, getting message that I cannot use this version of Mac OS X and cannot get back open old 3.6.10 format either since it has been replaced. How can I get this to work or replace previous application?

  • 1 èsì
  • 16 ní àwọn ìṣòro yìí
  • 12 views
  • Èsì tí ó kẹ́hìn lọ́wọ́ cor-el

more options

I have just downloaded Firefox 4 to replace 3.6.10 and am getting a message "You cannot use the application "Firefox" with this version of Mac OS X." How can I fix this or return to the previous version?

I have just downloaded Firefox 4 to replace 3.6.10 and am getting a message "You cannot use the application "Firefox" with this version of Mac OS X." How can I fix this or return to the previous version?

All Replies (1)

more options

Firefox 4 requires at least OS X 10.5 and an Intel Mac.

For Mac OS X 10.4.11 or Mac OS X 10.5.8 you can look at:

Firefox 3.6.x can be found here: