OS X Mountain Lion: The app is not from Apple or the Mac App Store
The app you tried to open wasn’t downloaded from the Mac App Store. This doesn’t necessarily mean that there is something wrong with the app. However, unlike the apps in the Mac App Store, this app has not been reviewed.
You can choose to override your security settings and open the app by anyway.
- In the Finder, locate the app you want to open. Most apps can be found in the Applications folder.
- Press the Control-key and click the app.
- Choose Open from the shortcut menu.
- Click Open.
OS X will remember this app as an exception to your security settings, and you will be able to open it in the future by double-clicking it.
For more information about protecting your Mac from harmful software, see this help topic: