I had the same problem than you and I got 10 drives attached to a 10 usb hub, so you will probably guess that it was hell on earth. The problem was that I always kept the individual switches on at the same time I turned on Vero 4k, and you know, drives turning on and off all the time. It seems to me that vero 4k can’t opperate with all drives at once from start, so what I do is to turn on Vero 4k and then I turn on all the switches and I’m not having this problem anymore
I hope it will help
regards