Thanks for the info, papageno.
I tried all of that, but I still can't get my ultralite mk3 firewire to show up.
When I type in sudo -uw / into terminal, it asks for a password. I put the password in and then it just goes to a new line of command.
I then open the installer package 1.6 in Pacifist and it looks different to yours. I don't have the System folder under Applications and Library.
I try and install everything anyway, and then restart, but not showing up in sound panel.
Can anyone please help?
***UPDATE:
It now works, as does Cuemix! YES!!
I'm not sure what happened. I followed all of papageno's instructions but there was obviously something I missed.
I went into security and privacy > general > and then unlocked it. Said there was something with a "j" in front of it that wasn't allowed. I allowed it, ran the Motu package again without Pacifist, restarted computer, and voila! showed up in audio preferences, and also Cuemix works.
I'm so happy.
Thanks again for posting this, papageno. I thought I was going to have to buy a new interface.
BTW, I'm running OSX 10.15.5 on a 2020 16" Macbook Pro with firewire400-800 cable into thunderbolt 2 adapter into usb-c adapter.
All seems to work fine currently.