In macOS Sierra, the Gatekeeper feature received an upgrade too, and you should check your settings to make sure they are set to cover your Mac the way you want.
If you do a search of your apps or settings for “Gatekeeper,” you won’t find any results. Here is the path to find your gateway settings. Open System Preferences, select Security & Privacy.
Let’s first make sure your Firewall is enabled. Select the Firewall tab at the top. If this window states that your firewall is off, you need to turn it on. Select the lock in the lower-left corner and enter your Apple ID password to make this change. Select the button to turn on your firewall. Next, select the Firewall Options button. Checkmark the boxes: “Automatically allow built-in software to receive incoming connections” and “Automatically allow downloaded signed software to receive incoming connections.” If there are any items listed in the box allowing incoming connections, such as iTunes or others, you can remove these by highlighting the item and clicking the minus symbol below. Select OK to save your changes and to close the box.
Now, select the General tab at the top. At the bottom, you’ll see a change that occurred in macOS Sierra. There is no longer an option to allow unsigned developers. This is the Gatekeeper setting. The default setting is to allow apps downloaded from the App Store and identified developers.
There is no longer an option to allow downloads from unsigned developers in this window, but there is a way to do so. If you still want this option, search Apple.com. I don’t want to list it in this article because I know some of my readers would try it just to see if they can, and it typically it isn’t in their best interest.
Click the lock in the lower-left corner so changes can no longer be made to your Mac. You can close the System Preferences box.
For 15 years, Scott Lindsay has helped tens of thousands of people better their skills, publishing more than 400 articles about Apple and Microsoft software, the computer and the Internet. You can reach Scott for comments or questions at ScottLindsay@live.com.