Firefox can't be opened after you install it on a Mac - How to fix

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  • Revision id: 76816
  • Created:
  • Creator: Joni
  • Comment: minor intro edit
  • Reviewed: Yes
  • Reviewed:
  • Reviewed by: jsavage
  • Is approved? Yes
  • Is current revision? No
  • Ready for localization: Yes
  • Readied for localization:
  • Readied for localization by: jsavage
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This issues applies to Mac devices only.

Apple has made a security change to Mac OSX 10.9.5 which causes the error message Firefox.app cannot be opened because the identity of the developer cannot be confirmed to appear when you try to install Firefox on your Mac.

Here are some steps you can take if you see this message:

Option 1 - Recommended

  1. Hold down the Control key while clicking on the Firefox file.
  2. Click Open on the dialog window.

Option 2 - Open Firefox through the System Preferences

  1. Click on the Apple icon at the top left corner of your screen and open System Preferences.
  2. Click on Security & Privacy, then the General tab.
  3. You'll see a message stating that the Firefox.app was blocked. Click on Open Anyway:
    blocked firefox mac