I wonder if it is possible to poll the Mac users to find a common setting, or hardware issue causing this? Or there is a deep, hard to find, bug in JRiver MC with only Macs. I just disabled my Norton Firewall and other protections. While I was doing it, I got several dropouts......but shortly there after I got several short drops and one was over a second long.
I also have Windows on my MAC.....by using the software Parallels. Do you have something similar? I disabled it completely as a test and I still got dropouts and turned it back on.
So I've eliminated Parallels & Norton, with Toslink and USB/DAC outputs. What else? I have a Mac laptop with an SSD. I can try that.