Appreciating this thread -- I've been trying to figure out why my older Midisport is not working after not having used it in a few years...then I borrowed an Uno, and that still didn't work. Now I know why!
Hopefully the suggestion to install the Roland driver works for some folks, but also be warned: I tried that route last night and ended up with an unbootable laptop. I was able to get it running again by reinstalling Catalina from Recovery Mode, but not until I spent a number of frustrating hours yesterday and today trying to back up my recent stuff using the command line (Terminal) from Recovery just in case I lost everything and had to revert to a Time Machine backup that's a few weeks old. Would rather have just spent the money on a new interface rather than waste all that time...and still have to buy a new interface.
Moral of the story: if you try the Roland driver, be sure to do a full backup of your Mac right before.
TvRMoogMusic wrote:I have a Midisport Uno which is not supported according to the M-audio website.
I downloaded drivers from Roland (UM-ONE MK2 DRIVER VER.1.0.3 FOR MACOS 10.15) and now it works perfect in OSX Catalina 10.15.7.
https://www.roland.com/global/products/um-one_mk2/downloads/
Perhaps this solution also works for you?