I don't have anything like DS4Win installed and I still get the RI.HID error nearly every time I start Unity, even the latest 2018 beta. I think they got rid of this issue in some 5.x or maybe even 4.x version a long time ago, but it's definitely back. It likely isn't the same issue because Rewired doesn't throw this HID error ever on my machine, unless Unity is just trying to open some other non-controller system devices that Rewired isn't. I did used to have DS4Win installed on my old dev machine and never saw this HID error with it. But who knows if they've changed something to open the HID device in exclusive mode or something.