Dealing with Gatekeeper

Apple introduced Gatekeeper as part of OS X Mountain Lion (and later brought it retroactively to OS X Lion). Gatekeeper is a great security feature that prevents applications from unregistered developers from executing on a user’s Mac. While this can prevent malware, it can also prevent users from installing or executing older apps that simply haven’t been updated since Gatekeeper’s introduction, and that includes many .saver screen saver files.

If you have an unregistered .saver file and Gatekeeper is enabled, you’ll run into an error when you try to follow the installation steps listed earlier. This is just Gatekeeper doing a commendable, but overzealous job.

Screen Saver Gatekeeper

To work around this problem, you have two choices. First, you can simply disable Gatekeeper. Power users accessing primarily unregistered software will have likely already chosen this path. Once disabled, you can install .saver files (and any other compatible applications) without issue.

If you’re unsure about your ability to recognize malware, or if you just want an extra layer of protection, it’s recommended that you leave Gatekeeper enabled. In this case, you can temporarily bypass Gatekeeper with a simple mouse trick. Just right-click on your .saver file and choose Open from the right click menu.

Gatekeeper Exception

You’ll see a similar Gatekeeper warning again, but this time you’ll also see an “Open” button at the bottom of the window. Click it to give the .saver file permission to install and avoid Gatekeeper’s standard limitations. Note that this method isn’t limited to screen saver files; it works for any unregistered app that would otherwise be blocked by Gatekeeper.