So I’ve also this i’ve had this issue when upgrading to High Sierra. 10.13.6
I was able to recover serialosc functionality follow this method from: https://superuser.com/questions/1135730/how-to-release-reset-serial-port-ftdi-devices-mac-osx
SOLUTION:
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Download the 2.4.2 drivers from FTDI’s website http://www.ftdichip.com/Drivers/VCP.htm and install. The install will succeed, BUT due to Apples built-in FTDI drivers they will not work.
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Reboot computer and enter recovery mode Via powering down and holding down CMD + R on reboot.
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In recovery mode open terminal from utilities at the top of the screen and type the following to tempraily disable System Integrity Protection:
csrutil disable
The computer will prompt you to reboot to make changes take effect.
- On reboot we now need to disable the Apple FTDI drivers (NOTE: this can be reversed at any time so do not worry). - open Terminal and type the following.
cd /System/Library/Extensions
sudo mv AppleUSBFTDI.kext AppleUSBFTDI.disabled
sudo touch /System/Library/Extensions
Now you will have successfuly have disabled Apple’s built-in FTDI drivers and replaced them with FTDI v2.4.
- Restart your computer in recovery mode. Shutdown, hold Command + R and open terminal in the Utilities tab. Enter the following to reenable Apple’s System Integrity Protection
csrutil enable
AT LAST! One final restart and then your USB serial devices should all be loading properly!
They had some other steps which I didn’t need so I have taken them out. Follow the link above if you want to see those.
mainly:
chgrp -R wheel FTDIUSBSerialDriver.kext
which is actually in /Library/Extensions not /System/Library/Extensions, and i’m pretty certain the permissions don’t need changing. And:
sudo mv D2zzHelper.kext D2xxHelper.disabled
which I didn’t have because I don’t use the D2 drivers…
Now I am able to plug / unplug my grids and get apps working. Previously it was working only if the grid was plugged in on boot.
However it still feels broken compared with how it used to work on previous versions of OSX. It takes a reasonable amount of time (2-4 seconds) for the device to appear in max7 serialosc. If it appears at all. Around half of the time, max or the maxpatch, need to be closed and reopened.