At first: "Windows 10 64 bit anniversary update" or newer is mandatory for Coffee Lake processors.
Does the iGPU appear in device manager?
IIRC there was another discussion, where people stated that it disappeared after installing discrete GPU.
Have you already installed Chipset (INF) driver?
If not, get it here:
Get following driver in ZIP format Download Intel® Graphics Driver for Windows* [15.60]
To bypass message "best driver is already installed" or "computer is not validated" install driver via have disk method as described at:
(ignore prolog about MS surface)
First off thanks for taking the time to answer.
I'm not sure if I have the Windows 10 64bit anniversary update, but I do have the latest 1709 build : 1709.16299.192
However, I don't know if I had the INF driver installed, so I just did install them.
The problem is that the only graphic card I see in my device manager is the 1080, so I can't follow your maneuver... Any clue why ?
Your Windows is OK.
Now check if your BIOS version is up-to-date
Solve 1060/1070/1080 VGA issue
Whatever that means.
Check setting in BIOS
Allows you to select which type of operating system to boot.
Auto Enables legacy option ROM only.
EFI Driver Enables EFI option ROM. (Default)
I remember another discussion (but forgot the link) where a user
physically removed the discrete GPU (after powering off)
booted the computer
installed the Intel driver successfully
inserted the discrete GPU again (after powering off)
then both GPUs were available
If that fails it might be an automatic mechanism in BIOS.
Bare in mind you have a desktop, no laptop with Optimus support.