Topic: Mac Big Sur: driver not loaded after reboot

Symptom: The audio interface only works directly after driver installation. The usual reboot after driver installation will no longer load the driver, so the audio interface is unavailable. This is reported with macOS 11.4, but also with 11.3.1.

Cause: Not fully clear. According to user feedback this can happen after OS updates, other companies driver updates and RME driver updates.

Underlying cause: It seems that the internal data base of macOS kernel extensions and security allowances gets corrupted. While the driver clearly had been allowed before the OS now acts as if it was not. On reboot, that is.

Fix: has to come from Apple.

Workaround: according to user feedback it is possible to refresh the internal list and bring back the former, working system. Forum user ndc described how to do that (https://forum.rme-audio.de/viewtopic.ph … 60#p170260):

- boot into recovery mode

- open Terminal

- run the kernel extension panic medic boot command by typing:

kmutil trigger-panic-medic --volume-root /Volumes/YOUR_HD_DRIVE_NAME

Default hard drive name is Macintosh HD, where the space has to be omitted. Else use your custom drive name.

This action removes the kext-consent entries. These can now be re-approved after a reboot:

- Reboot into normal mode

- Go to Security&Privacy and allow all items currently not allowed.

- It might be necessary to install the RME driver again to trigger a kext consent entry notice. If you reinstall make sure not to click reboot too early., first finish the driver installation and the Security&Privacy request.

Matthias Carstens

Re: Mac Big Sur: driver not loaded after reboot

I've now seen three cases where the installation of third-party hardware and software/drivers (external SSDs and an audio interface) triggered this issue for an RME interface...

Daniel Fuchs


Re: Mac Big Sur: driver not loaded after reboot

According to user feedback when updating to the latest 11.5.1 the above procedure needs to be performed again, even if you had done it before and everything worked.

Matthias Carstens


Re: Mac Big Sur: driver not loaded after reboot

A helpful note of RME user Pål Svennevig:

To help with how to do break outs of space in the terminal:
Spaces has to be broken out with a backslash. You can often use double quotes as well, but not always.

/Volumes/Macintosh\ HD

as noted earlier this might also work

"/Volumes/Macintosh HD"

If you use TAB completion when typing a command in Terminal, it will fill out the break outs for you.
The simplest is of course to rename your boot volume, since Macintosh HD is so little nerdy!!!

To elaborate on these break outs, it gets even harder if someone uses () in file or folder names, for instance
My Music (2021) would be in terminal:

My\ Music\ \(2021\)

Not easy at all! And this is why we avoid spaces and pesky characters as () in file and folder names in post production at all costs.
It simply makes it much harder to automate and script in bash, zsh or Pyhton.
my_music_2021 or my-music-2021 is so much simpler to automate!


Matthias Carstens