I'm on a late 2011 MacBook Pro 8,1 with i5 processor. I am trying to connect an audio interface. I have been told that it is due to KEXTs being blocked. In OS 10.13.6 in the Security and Privacy tab Privacy Menu, the last blocked application is supposed to show. There should be a button to allow it as an exception. OS 10.13.3 Security feature added in High Sierra does not allow for this. There must be a way to allow for exceptions.