Hi Bulycui -
Since you mention the Ultralite, I gather your MIDI connection is the MIDI i/o on the Utralite audio interface -- in that case there should be no need for the MT4 driver, the MIDI i/o on the Ultralite would require the MOTU MIDI driver. ( Just FYI the old Emagic driver can be downloaded at https://support.apple.com/kb/dl991?locale=en_US but, again, you shouldn't need this for your setup -- it's not a generic MIDI driver, but one only for specific older Emagic MIDI hardware interfaces. )
A couple of things come to mind -- you may have tried these, but I'll mention them anyway..
- First, what are the specs of your system? (Ultralite model, Mac model/year, ports on the Mac)
- How is the Ultralite connected? USB2, USB3, Thunderbolt, FireWire, FW->TB adaptor, etc..
- What is the MIDI device you're using (keyboard, control surface) that's plugged into the Ultralite's MIDI in?
- If the Ultralite is connected via USB, is it connected to a USB hub? If so, try a direct connection instead -- audio/MIDI devices often have issues when connected through a hub, and it's generally recommended that that be avoided.
It sounds like you're plugging the actual MIDI device (keyboard, whatever) into the MOTU's MIDI in with on old-fashioned MIDI DIN cable -- as a test, it might be worth trying to connect the MIDI device without using the MOTU MIDI i/o (if possible) to see if that's where the problem lies:
- If the MIDI device (keyboard) also has a USB MIDI connection, can you try plugging it directly into the computer (again, no hub) via a USB port? This may require a MIDI driver for direct connection, unless the MIDI device is class-compliant, which means it'd use the Apple MIDI driver built-in to the OS.
- If the MIDI device only has older MIDI (DIN) connections, can you try a different MIDI device with a USB MIDI connection, as a test? Ideally, this would be a MIDI keyboard that uses the OS's built-in MIDI driver (class-compliant), to eliminate the possibility of another driver issue. (You could temporarily remove the MOTU driver (running the audio through the built-in audio output if need be) to eliminate that driver from the equation while testing the USB MIDI connection).
Anyway, I hope you're able to resolve the issue -- please let us know if/when you do find a solution, since this kind of problem is not uncommon..