How to open apps from an unidentified developer in OS X Mountain Lion

If you're running OS X Mountain Lion on your Mac there's a feature you should know about called -- Gatekeeper. The primary function of Gatekeeper is to prevent malware like viruses and trojan horses from getting their hacking hooks into your Mac. Gatekeeper does this, by default, by only allowing apps that are downloaded from the Mac App Store or from "identified and trusted developers" be opened.

But what if you know the app you're trying to open is safe even, though the developer didn't or couldn't get a trusted certificate from Apple? (For example, Jailbreak software). There are a few ways to bypass Gatekeeper if you run into this issue. Follow along and we'll show you how.

How to bypass Gatekeeper on a case-by-case basis

This is the method we recommend using. It gives you Gatekeeper's full security, but the flexibility to open occasional unsigned apps when you know and trust them.

If you attempt to open an app you downloaded from a source other than the Mac App Store, and get the popup below, you'll need to override Gatekeeper in order to open it. As always, make sure you know where the app came from before overriding Gatekeeper.Gatekeeper can't open app OS X Mountain Lion

Instead of double-clicking on the app in question to open it, here's what you do:

  1. Ctrl+click or right click on the app and select Open from the contextual menu.
  2. RIght click to open bypasses Gatekeeper in OS X mountain Lion
  3. This time you'll see the popup below instead of a message saying the app can't be opened at all.
  4. Gatekeeper confirm open app dialog box
  5. Click Open if you're sure that the app is from a trusted source.

The app will open and you'll be able to use it normally now. You may get one more popup from time to time verifying that you're sure, but you can confirm them as well, as needed.

How to change Gatekeeper settings to allow or disallow unidentified apps

We DO NOT recommend this approach for anyone who doesn't constantly and consistently need to open non-Mac App Store, non-signed apps. In other words, if you do this, you're someone who knowingly gives up the protection of Gatekeeper because your work or other activities require it, and you know full well what you're doing.

Consider yourself warned. Again.

  1. Launch System Preferences and click on it.
  2. System Preferences in Mac OS X
  3. From here click on the Privacy & Security icon in the top row.
  4. Mac OS X Mountain Lion System Preferences
  5. The General tab is where we want to be.
  6. If everything is grayed out, click on the lock in the bottom left hand corner and type in your administrator password. This will allow you to make changes to your settings.
  7. Type in admin password to change preferences in OS X Mountain Lion
  8. We recommend using the middle setting which is Mac App Store and Identified Developers. You can also choose between Mac App Store Only for tighter security or Anywhere which will allow any app to be opened regardless of the source or developer.
  9. Allow applications downloaded from Mac App Store and identified developers OS X Mountain Lion
  10. Once you've made your changes you can go ahead and exit out of System Preferences altogether.

The bottom line

Again recommend using the first option (contextual menu "Open" command) and leaving Gatekeeper on one of the first two settings as opposed to allowing apps from anywhere to be opened and run on your Mac. This will help prevent any malware or malicious apps from doing any damage to your Mac.

If you have other OS X questions or need help with features like Gatekeeper, make sure you check out or OS X forums as well!