K70 RGB issue: keyboard not found

I upgraded my K70 mx red to a K70 RGB mx brown I have the newest firmware installed and also the the updates for the corsair software. My PC runs with win 10 pro and has a Maximus VIII Ranger, i7 6700k, 16gb fury ram and an nmve pcie ssd. Every time I Start my pc, my keyboard isn't working. I have to unplug it and plug it in again. Then it's working fine. But why? At the first 2 days, there was no mistake. I tried the bios switch at the keyboard, but it did not helped me. It's not the led's not glowing, the whole keyboard does not work. Anyone with the same issues or an idea to fix it? I hsd no problems with the non-rgb one