OS X Mountain Lion: Protect your Mac from malware
OS X Mountain Lion has many features that help protect your Mac and your personal information from malicious software, or malware. One common way malware is distributed is by embedding it in a harmless-looking app.
You can reduce this risk by using software only from reliable sources. The settings in Security & Privacy preferences allow you to specify the sources of software that run on your Mac.
- Choose Apple menu > System Preferences, click Security & Privacy, and then click General.
- Choose the software sources you allow.
Option Description Mac App Store: Allows apps only from the Mac App Store. All the developers of apps in the Mac App Store are identified by Apple, and each app is reviewed before it’s accepted. OS X checks the app before it opens the first time to be certain it hasn’t been modified since the developer shipped it. If there’s ever a problem with an app, Apple removes it from the App Store. Identified Developers: Allows apps from the Mac App Store and applications from identified developers. Although apps from outside the App Store are not reviewed, the identified developers are registered with Apple. If problems occur with an app, Apple can revoke its authorization. OS X checks the app before it opens the first time to be certain it hasn’t been modified since the developer shipped it. Anywhere: Allows all apps from anywhere. This setting turns Gatekeeper off and your Mac behaves the same as previous versions of OS X. However, this is the least secure setting because there is no verification of the source of the app, and no checking to see whether the app has been modified or broken.
In addition to apps, other types of files may or may not be safe. Scripts, web archives, and Java archives have the potential to cause harm to your system. Of course, not all files like this are unsafe, but you should exercise caution when opening any such downloaded file. An alert appears when you first try to open these files.
To open the app, press the Control key, click the app, choose Open from the shortcut menu, and then click Open.
In the future, the app is considered an exception to the security settings and you can open it by double-clicking it.