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