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M-Audio (Avid) Fast Track Ultra - El Capitan Workaround

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IORegistryExplorer is a useful tool that anyone should use before trying anything.


Many laptops, mac or not, have keyboard and trackpad connected to an internal USB bus, so modifying system USB kexts can prevent their drivers to load.

While experimenting, keep a standard USB mouse nearby, plug it and use keyboard viewer to reverse things if you loose your internal keyboard/trackpad. Should be faster than reinstalling if you backed things up as advised. ;)


Use IORegistryExplorer to find what driver is used for your keyboard/trackpad : keep in mind that the workarounds described in this post simply revert USB drivers in Sierra or ElCapitan to Yosemite versions. You just need to find the matching Yosemite drivers for your keyboard/trackpad. It's probably not that complicated.

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On 6/12/2016 at 8:03 AM, oliveiro said:

I've had more time to further experiment : my attempts to modify the Fast Track Ultra drivers all failed.


But I've found another way, much cleaner, much lighter. I suspected the M-Audio driver was not using the whole IOUSBFamily and plugins, and checking the IoRegistry in Yosemite I saw that the M-Audio kext was simply relying on AppleUSBXHCI.kext (found inside the Plugins folder of IOUSBFamily.kext in Yosemite).


My system is USB 3.0 based, so it's using XHCI, maybe older systems are relying on older EHCI OHCI or UHCI. So I did the following modifications on the attached file : this is a IOUSBHostFamily.kext from a clean install of ElCapitan 10.11.5 :


  • I removed AppleUSBEHCI.kext, AppleUSBEHCIPCI.kext, AppleUSBOHCI.kext, AppleUSBOHCIPCI.kext, AppleUSBUHCI.kext, AppleUSBUHCIPCI.kext, AppleUSBXHCI.kext, AppleUSBXHCIPCI.kext from Plugins folder.
  • I added previous Yosemite versions of AppleUSBEHCI.kext, AppleUSBOHCI.kext, AppleUSBUHCI.kext, AppleUSBXHCI.kext (taken from IOUSBFamily.kext Plugins folder, from a clean install of Yosemite 10.10.5) inside Plugins folder.


You can do the mods yourself, or use the attached file. Remember, if you're not familiar with kext installation or modification, do backup first, especially if you're trying this on your main system. This is for ElCapitan 10.11.5.


  1. On real Macs, you have to disable SIP first (See here).
  2. If you used the first workaround described in Posts 1 & 2, undo it all. Restore original files, rebuild system caches and reboot.
  3. Open Finder, go to /System/Library/Extensions/, browse the folder till you find IOUSBHostFamily.kext. COPY it to a safe folder.
  4. Then use KextUtility ( http://www.insanelymac.com/forum/topic/140647-latest-kext-utility-el-capitan-super-speed-edition/ ) to install the modded file into /System/Library/Extensions/. When you launch KextUtility, it asks for password, if you enter your password, the app runs full task service : it repairs permissions on system folders and rebuilds system caches. I does not do any harm, but you don't need that at this step : just cancel the password dialog. You can then drag and drop the modded kext on the app window, enter your password, and wait till it says "finished" and shows the "quit" button.
  5. reboot, at boot choose "ignore caches" option (Not sure if it's necessary on real macs, it's just to make sure all kexts are reloaded)
  6. Once you're back to your desktop run KextUtility again, and this time enter your password to run full task service.
  7. Reboot normally.


Collateral benefit on my system, USB 3.0 now works without the need of edits on my Intel system (obviously, because the concerned kexts are now replaced by Yosemite versions)


So far, I have not noticed any problem on my system.


Please, post here if you meet any trouble.


hello guys, its 2019 and i have the same problem of everyone here. i'm on a macbook pro 2009 with mac os x 10.11 el capitan and my M-audio fast track ultra 8R doesn't work with it.

I was about to get started on @oliveiro 's instruction but he's link to the "IOUSBHostFamily.kext.zip" doesn't exists anymore. Can some one help me out here? 

PS: i can't access to a clean Yosemite. 


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