So I bit the bullet and bought the Ultralite Mk5
After some experimentation and debugging errors, the short answer is YES it works under Windows 7 - this requires a fairly simple process of modifying a few lines in the inf files which accompany the drivers, putting Windows into test mode, then manually installing the drivers. I've not had any luck with the usb MIDI driver as yet (not needed in my case) but the asio and usb network drivers both install successfully and the device works perfectly (including connecting to Cuemix) and is very stable at low latencies as advertised. Firmware updater requires Win10 though, so just run this from a Win10 laptop.
Few points to note:
1) Windows will need to stay in test mode if you want the drivers to work, if you want you can put it back into normal mode for security purposes when installing other software, on internet etc.
2) You'll need to update the driver/INF file each time you install a software/driver update.
3) If you prefer you can update the copies of the INF files which are installed at C:\Windows\System32\DriverStore\FileRepository (little bit trickier to find, however these are the driver files you see when you update the driver and select 'Let me pick from a list of available drivers', so updating these will avoid having multiple copies)
I've detailed the required steps below if anyone is interested, also attached are my modified INF files after my last driver update.
Cheers!
Steps to update drivers:
1. Put Windows into test mode. (From command prompt run: bcdedit -set TESTSIGNING ON and enter. Reboot. you should now see a small 'Test Mode' in the bottom right hand of the screen).
2. Locate the copies of the driver files from the driver setup/installation process at C:\Program Files (x86)\MOTU\Gen5\x64\DriverPackages
3. Make a backup copy of the above folder
4. Edit the MOTUgen5NULL.inf (for Generic USB Driver) and MOTUgen5ECM.inf (for USB Network Driver) using Notepad, making the below changes and save.
5. Manually update each device driver by pointing them to the above directory with the driver .sys files and accompanying modified inf files. (Open Device Manager, right click on each MOTU device driver, choose ‘Update Driver’, ‘Browse My Computer for Drivers’ and locate/select the folder C:\Program Files (x86)\MOTU\x64\DriverPackages)
INF file Changes
File: "MOTUgen5NULL.inf" (for Generic USB Driver)
Replace text:
Class=USBDevice
ClassGuid={88BAE032-5A81-49f0-BC3D-A4FF138216D6}
with
Class=USB
ClassGUID={36fc9e60-c465-11cf-8056-444553540000}
File: "MOTUgen5ECM.inf" (for USB Network Driver)
Replace text:
[ControlFlags]
with
; ================= Device section =====================
[ControlFlags]
ExcludeFromSelect = *
[DestinationDirs]
DefaultDestDir=12
Then under ‘MOTU USB Ethernet Adapter’ section, replace text:
[MOTUgen5ECM.ndi]
Characteristics = 0x4 ; NCF_PHYSICAL (USB)
with
[MOTUgen5ECM.ndi]
BusType=15 ; PNPBus