How to open an application from an unidentified developer?

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By default, the Mac OS only allows users to install applications from 'verified sources.' In effect, this means that users are unable to install most applications downloaded from the internet or stored on physical media without receiving the error message below:

The application can't be opened because it is from an unidentified developer.

Users can follow the directions below to prevent this error message from appearing in one of two ways:

For more information about this message, please visit Apple's KB article on the topic: http://support.apple.com/kb/HT5290.

  1. Open the System Preferences. This can be done by either clicking on the System Preferences icon in the Dock or by going to Apple Menu > System Preferences.

  2. Open the Security & Privacy pane by clicking Security & Privacy.

  3. Make sure that the General tab is selected. Click the icon labeled Click the lock to make changes.

    Click the lock icon in the lower left-hand corner

  4. Enter your username and password into the prompt that appears and click Unlock.

    Enter your credentials and click Unlock in the pop-up window

  5. Under the section labeled Allow applications downloaded from:, select Anywhere. On the prompt that appears, click Allow From Anywhere.

    Select the Anywhere radio button and confirm your selection in the pop-up

  6. Exit System Preferences by clicking the red button in the upper left of the window. You should now be able to install applications downloaded from the internet.

  7. While holding down the control key on your keyboard, click the application's icon once to make a dropdown menu appear.

    Control+click to open the context menu, then select Open from the top

  8. Select Open from the menu. A new window will appear.

  9. Click Open in that window to launch the application. You should only need to do this once per application, on the first launch. After that, you'll be able to launch the application any way you like.

    Confirm that you want to launch the application

  10. At this point the application should be able to open successfully.