Just bought a NUC6CAYH and installed Windows 10 Pro x64 a couple of days ago. A few minutes after Windows Update had installed the Intel graphics driver, the display connected through the NUC's VGA port started to turn black for a second or two every couple of minutes. During the Windows installation and before the box was connected to the Internet (and Windows was able to do updates), the problem did not exist.
To get rid of this annoying behavior, I started to look for updates and flashed the BIOS up to version 41 (from 38) and installed graphics driver 4849, which was just released a couple of days ago. Unfortunately, that did not solve the problem. I started searching this forum and found that many others are having the same problem. As outlined in other threads, this clearly is a Intel Windows driver problem. As others have tried, I installed Linux (Ubuntu 16.04.3) and I am not experiencing this annoying effect under Linux. So please fix this problem in your Windows driver - I specifically picked this box because of its VGA connector in support of my old monitor. It is shocking to me that a company like Intel is not capable to solve a driver problem that has been reported by so many so often for months.