This weekend I was playing around with Openvpn to a new site. I use Tunnelblick for this, but this time was the first time after I had upgraded my Mac to High Sierra (10.13.5). Suddenly my vpn connections didn’t want to load anymore.

Tunnelblick threw these errors to me:

I was running a beta, so first thing was to install the stable release, but the message remained.

This link: https://tunnelblick.net/cKextLoadError.html helped me. In high sierra to use or add modules in your kernel, sometimes it is necessary to give user consent.

These kernel extensions don’t require approval:

• Extensions that were installed before upgrading to macOS High Sierra
• Extensions that are replacing previously approved extensions
• Extensions that are allowed to load without user consent by using the spctl command while started up from macOS Recovery
• Extensions that are allowed to load via the Kernel Extension Policy

So in my case, I was using Tunnelblick before, so it had to be something else. That meant, that I was in situation (2) “There may be incompatible kexts already loaded”.

To find that out on mac you open a terminal and use this:

Tunnelblick uses customized versions of the kexts from tuntaposx, so this must have been a leftover from previous versions. I like the next sentence on the tunnelblick website so I want to share it with you “Recent versions of Tunnelblick try to be “good citizens” by loading kexts only when needed, and unloading them when they are no longer needed.”.

This means, that I (most likely) don’t need these modules, so I unloaded them:

And there we go. After doing this, the vpn tunnel came up and everything worked as before.

As always, questions, remarks? find me on twitter @vanpupi