Windows 10 will reach EOS (end of support) on October 14, 2025. For more information, see this article.

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

The application “Firefox” can’t be opened.

  • 1 reply
  • 1 has this problem
  • 5 views
  • Last reply by OBW47

more options

Hi. I am running MacOS Catalina 10.15.7. I always use Firefox as my browser as it is the BEST. After updating I get the following error message when I try to run Firefox: "The application Firefox can't be opened" I have tried uninstalling and reinstalling to no effect. When I boot my MacBook Pro into SAFE MODE, Firefox opens and runs. When I boot back into normal mode I get the same error message. Help! Any suggestions.

RD

Hi. I am running MacOS Catalina 10.15.7. I always use Firefox as my browser as it is the BEST. After updating I get the following error message when I try to run Firefox: "The application Firefox can't be opened" I have tried uninstalling and reinstalling to no effect. When I boot my MacBook Pro into SAFE MODE, Firefox opens and runs. When I boot back into normal mode I get the same error message. Help! Any suggestions. RD

All Replies (1)

more options

Perhaps something in the linked document will help.

https://support.mozilla.org/en-US/kb/firefox-wont-start-find-solutions