How to fix the "can't be opened because it is from an unidentified developer" error message on Mac OS X when opening a downloaded app.

The Mac OS X error message saying an app “can’t be opened because it is from an unidentified developer” is a warning message when users attempt to open or install an application that was not downloaded from the App Store.

Apple still allows users to install downloaded software but there are some additional steps that users need to take in order to do so.

The short term fix to avoid this error message is to right-click on the app in question and choose the “open” option. You will receive a different error message saying the app “is from an unidentified developer. Are you sure you want to open it?” In the window of this error message, however, the user has an open to click open and the app will open normally.

See Also: Mac OS X – Change / Set Default Application for File Type [Video]

Users can also configure a setting on their Mac OS X computer so that when a new app downloaded from the web is opened with a double click, the option to open the app will immediately be available.

To do this, users must navigate to their system preferences, go into the “Security and Privacy” section and, in the general tab, choose the radio button option that says “Allow apps downloaded from: Anywhere”.

For a more detailed walkthrough, take a look at the video embedded at the top of this post.

As always, if you find this video helpful, I would really appreciate a thumbs up and you may also want to think about subscribing to my YouTube channel.

Anson Alexander

Anson Alexander is a blogger, author, SEO expert, teacher, and tech geek. As the founder of, Anson works full time writing, editing, and producing content for his site and providing technical and business services to clients. He has a BS in international business and information systems from the University of Tampa. In his free time, Anson plays video games, enjoys nature, spends time at the beach, and loves to travel.

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