I have an RME FireFace UCX audio interface connected to a 2014 5K Retina iMac with a Fusion Drive and for a few months I have been experiencing very annoying audio skipping/stuttering issue. Here is an example (heard about 4 and 24 seconds in): https://soundcloud.com/vladobizik/ufx-stuttering/s-spVRa I doesn’t occur when using the iMac’s internal speakers, it’s isolated to the UCX. I use FireWire (through the Thunderbolt port) for connection but the problem appears also when using USB. It happens at all sample rates, although I think the stuttering is somewhat more pronounced when using higher frequencies. I tried all the standard troubleshooting measures, e.g. restarting CoreAudio (sudo killall coreaudiod). I have even tried re-installing the system. I tried connecting my brother’s older FF 400 and it happens with it too. It would seem that the probles is with drivers or the computer, not the specific FireFace device itself. I don’t know where else to look. It happens with apps playing audio. But it tends to happen more with a pro audio app (e.g. MainStage) open. I on the latest software, macOS 10.12.5 but it has been occurring since 10.12.3. I am using the latest RME drivers (3.32 in the case of the FW driver). I have had the interface for years and used it on the same computer for two and a half years and it has only recently started happening. Is there something I am overlooking, can you help me with the issue?