I updated my Mac (iMac) and Mac OSX to Catalina and my KB37 interface stopped working, Tried a UX2 and same result -- flashing clipping (red) lights indicating drivers not loading. Tech support told me it was a security issue but instructions could have been clearer, so posting them here in the hope they will be useful. 1. Install driver package and restart computer. 2. Go to System Preferences and then Security & Privacy 3. Go to the General tab and look for "Some System Software was blocked from loading" 4. Unlock (so type in password) and click on Allow 5 Select Line 6 checkbox I was told that you should not wait to long (less than 15 minutes) after the restart to do the security setting. Hope this helps.