I tried installing Windows 10 on the M.2 SSD and it did not show up in the list of harddrives (none showed up since I only had the M.2 SSD connected). Then I installed Windows 10 on an old SSD of mine and now from the OS on this drive I do not see the 950 Pro in the device manager either.

I have the strong feeling that something is wrong with my Samsung 950Pro; since it just looks like nothing is connected. Since the board is working flawlessly I think if there is a hardware problem its on the M.2 drive.

You need to set it up in the Bios first.

Hello N0va. I remember having this problem too, but let's see if my gray matter retained what I did.

Definitely remove all other devices and just leave the Sammy
Did you clear the CMOS? You mentioned you have made settings adjustments, might as well at this point just start like new. Check the mobo manual how to clear the CMOS. Later once we get the Sammy to be seen you can go back and make whatever adjustments in the BIOS for those things.
Go in to the BIOS after clearing, go to "Boot" and make sure Fast Boot is disabled. Then scroll down and make sure CSM is also disabled. Save changes and reboot
Go back in to the BIOS and go back to the "Boot" tab, scroll down to Boot Option Priorities which is in gray. Below that and to the right it should say "Windows Boot Manager (samsung.....)

See if this helps. I remember that it was a pain to install, but clearing things and starting fresh makes the drive appear. I have even read to reflash your BIOS (1701) as another method, shut down completely, wait 30 seconds and then boot up again in to the BIOS and this sometimes works too

FYI, when the BIOS does finally find the Sammy and you begin the installation of Windows 10, do not use the Samsung NVMe driver. Just use the Microsoft NVMe standard driver as this forum that I hang out found a problem where in the S.M.A.R.T. readings the "Unsafe shutdowns" is increasing when there has never been a shutdown. My system had the Samsung driver and already it says I have had 12 unsafe shutdowns. Even on days when I had no shutdowns it records it as unsafe. I uninstalled the Samsung driver and just running off the standard Microsoft one and I am at 12 since. Others are in the hundreds.
Here is the site looking at this and were providing as much as we find out on this

http://www.win-raid.com/t2041f38-SAMSUNG-PRO-NVMe-SSD-unsafe-shutdowns-NVMe-driver-W-x-unexpected-sh...

FYI and hopes this helps

Thank you Denaba for your tipps; I will try them out as soon as I can. I send back my Samsung 950 pro and bought a new one which should arrive soon. Apart from my problems with its installation I was not very happy with the distributor; I only got the drive, no manual, warranty information or original Samsung packaging. So even if the old one was not broken I just wanted a product in original packaging from a more respectable distributor; who knows what kind of crap they tried to sell me.

I will reflash my Bios and start over with completly plain bios settings and follow your steps. I think I have not tried to disable "fast boot" so maybe that will help.

Thank you all for your help and input!

I "solved" the problem today. Actually it solved itself. I got my new 950 Pro, flashed my Bios and plugged my new SSD. I keept the GPU and the optical drive connected but disconnected all other USB and SATA devices. The drive was recognized instantly in the BIOS and the Windows installation worked without any problems or further adjustments. So my inital thought was right: the Samsung 950 Pro, which I got first was just broken.

At least from my experience there are no adjustments necessary to install Windows on a Samsung 950 Pro with the Asus Maximus VIII Hero with Bios version 1701. Except a working SSD of course.

Thank you all again and this thread can be closed as far as I am concerned.