Hello.
I think you have same problem as I had last year (post with video is pined). It's not just a 3D-coat problem, but I've tested that FreeCAD and Rhino3D also have this problem. I found the reason why this is happening on the Rhino3D website. The problem is caused by Nahimic dll from audio driver (99.9%). I have Asus STRIX RAID DLX sound card and driver use Nahimic dll for something. After I disable the part of the driver that used this dll, everything start working normal. You can try shutdown all part of audio driver in Task manager (mainly part with Nahimic) and you see if that works.
