I just updated my early 2015 13" Retina MacBook Pro from OS X 10.11.2 (where everything worked fine) to the latest 10.11.3 a few days ago, due to some security fixes in OS X. Since then, my FireStudio Mobile constantly drops the audio connection (and sometimes comes back after few seconds). I am running the FSM with a Thunderbolt/DisplayPort-to-FireWire adapter, which has worked fine just until the latest OSX update. Now, the sync LED starts blinking red/blue after a few seconds and eventually the FSM completely shuts off.
I also double checked the FSM with my late 2012 Mac mini, which still runs on OS X 10.11.2 and found it working fine, without any audio disconnect or any sync issues.
I should mention that I am using Universal Control 1.7.3 build 5742 (date of the downloaded .dmg file is 2 Nov 2015 20:55), which is driver version 18.104.22.168752, according to the application's main screen. And I also tried the complete uninstall and re-install according to some other knowledgebase article I found.
It seems there is an issue with one or some of the security fixes in 10.11.3 with this particular OSX version of UC 1.7.3 causing the connection to be disrupted. Any solution to this? Thanks!