Mac OS X has many security features – the most important of which are default settings that protect Mac users. A recent addition is ‘Gatekeeper’ which has a function of preventing some applications from running on your Mac.
The default setting protects users: Only software downloaded from the Apple-curated Mac App Store can be opened.
If you want to install any of my recent plugins, that is a problem. I don’t yet sell software on the Mac App Store.
There are two ways around this: use an alternate method to open my installers, or change the Gatekeeper setting to allow my installers to open normally.
Run my installers using a shortcut
Instead of double-clicking the installer, control- or right-click it to see a shortcut menu. Choose Open from the menu. You’ll see a different message:
Click Open. If you need to run the installer again, OS X will allow you to do this by double-clicking as normal.
Change OS X security settings
To change the OS X security settings, choose System Preferences… from the Apple menu, and click Security & Privacy:
You’ll see that the default setting is to only allow applications downloaded from the Mac App Store to run: 
You’ll see that the setting you need to change is greyed out. To change it, click the lock and enter your password. Change it to Allow applications downloaded from: Mac App Store and identified developers.
Close the Security & Privacy panel to finish.
This setting isn’t as safe as only allowing applications from the Mac App Store. But I’m an identified developer. This means if I include unapproved software in any of my applications, Apple can instantly disable all my apps wherever they are installed.
