Smaart I-O Isn't Working Properly in OSX 10.11.4
If you are having problems with Smaart interacting with your Rational Acoustics Smaart I-O, and you are running OS X version 10.11.4 or newer, you are likely experiencing a problem with the recent OS X update.
In the 10.11.4 OS X update, the Smaart I-O is renamed internally to "Smaart I_O", which breaks the communication between the Smaart I-O and Smaart. You can verify this if the device is named "Smaart I_O" in Audio/MIDI Setup.
To resolve the problem, perform the following steps: