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How to Fix Extensions Blocked by Gatekeeper in macOS 10.13 High Sierra

In our recent post titled macOS 10.13 High Sierra Significantly Improves DisplayLink Performance & Stability we talked about how the latest update to macOS improved behavior when using a DisplayLink product (such as the Plugable UD-ULTCDL docking station). To go with that, we wanted to take a moment to discuss the Gatekeeper security feature introduced back in OS X 10.7 which has gone through some changes in High Sierra that may affect installation of some 3rd party device drivers used in devices from Plugable and other device manufacturers. For Plugable, the issue will only impact our products which don’t have drivers already built-in to macOS, such as our USB Docking Stations, USB Graphics Adapters, and USB Ethernet Adapters. Essentially this issue can affect any extensions not developed by Apple. Thankfully if you encounter this, there’s a simple process to fix. Keep reading for additional information and instructions.

In macOS 10.13 High Sierra, when installing new software and extensions, Gatekeeper now requires users to manually approve any new third-party extension before the computer can load and make use of the extension that was installed. This is important as many devices rely on extensions to function properly, and in some circumstances it can look like the software to power a device was installed but the device still doesn’t work. When this happens, users will see the below message:

 

 

If you suspect Gatekeeper is preventing an extension from loading, follow the below steps:

  1. Open System Preferences and navigate to the Security & Privacy section.
  2. In the General tab, look for a message at the bottom of the window stating “System software from developer DEVELOPER NAME was blocked from loading”, like in the screenshot below:

    For Plugable products, the developer listed in the message should be “DisplayLink Corp” for DisplayLink powered products (such as docking stations that do not use Thunderbolt 3 technology) and “WEI LU SU” for Plugable ethernet adapters that use ASIX chipsets (as of the time of writing this, all Plugable USB network adapters use ASIX chipsets).
  3. Click Allow, and from there macOS should now be able to properly load and use the extensions and software that were installed.
  4. Test things out! In some instances, you may need to restart the computer for the extension to properly load. So if it doesn’t work immediately, reboot the computer and the extension should load correctly.

 

Once an extension from a developer has been allowed, this makes the developer a ‘trusted’ source. Meaning that future extensions that are installed from the same developer should not be prevented by Gatekeeper from loading and should not need to have these steps repeated. However, software and extensions from other developers will encounter this same issue and you will need to follow these same steps.

 

For additional information on Gatekeeper and the behavior described in this post, check out the below Apple and DisplayLink support documents!

Feel free to share your experiences with High Sierra in the comments below, and if you’re having issues installing driver extensions for any of your Plugable products, please email support@plugable.com and we’ll be happy to help!

OS X: About Gatekeeper

Technical Note TN2459: User Approved Kernel Extension Loading

macOS High Sierra: Video Functionality Not Enabled

4 comments on “How to Fix Extensions Blocked by Gatekeeper in macOS 10.13 High Sierra”

  1. Kent West Reply

    That’s fine if you’re only installing on one or two machines where logging into the GUI is not onerous. But if you’re installing to dozens or hundreds of Macs, you need a scripting solution.

    An “almost” solution is to enter the command from Terminal/SSH (as root/sudo):

    # spctl –master-disable

    To get the current status of Gatekeeper:

    # spctl –status

    And to re-enable Gatekeeper:

    # spctl –master-enable

    But this is not a 100% solution, as some items can still be blocked (e.g. DiskKeeper’s driver), and can leave the install in a partially-installed state that has potential to wreak havoc on your system (as is the case with DiskKeeper – not really installed, but installed enough that you can’t make any changes to the system, and you can’t uninstall DiskKeeper to make the machine usable again).

    I would love for someone to publish a command-line driven fix that actually completely disables Gatekeeper, not just mostly.

    • Patrick T Reply

      Hello Kent,

      You’re correct that using these commands will temporarily disable Gatekeeper (partially, but not completely). The spctl –master-disable command will work if you enter it prior to installing the driver. From our experience you need the sudo version of the command (sudo spctl –master-disable) though. After installing, use the sudo spctl –master-enable to re-enable.

      Another solution via Terminal we’ve found to work is as follows. After installing the driver, you can use the kextload command to force it to load (this works because Gatekeeper prevents it from loading and this forces it to load anyway). As with the other command, we’ve found using the sudo version is best. Full command is sudo kextload /PATH/TO/EXTENSION but you’ll need to know the path to the extension being blocked.

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