I tried to transfer some ICCs I'd created on a PC using QTR-Create-ICC.exe to a Mac (Sierra). I copied them to Library\Colorsync\Profiles. But although the system could see them, Print Tool couldn't. Ultimately I had to copy the measurement data to the Mac and recreate them on the Mac and then replace the PC ones with the Mac-created ones, and then Print Tool displayed the ICCs.
Why is this?