I found a solution, that worked for me. So far no reboots on shutdown anymore!!
All I did was uninstalling the Intel® Rapid Storage Technology (Intel® RST) Software. That sealed the deal for me.
And just in case to make sure I installed the latest Intel chipset drivers from Intels website.
https://downloadcenter.intel.com/Det...?DwnldID=20775Little Tip for chipsetdrivers:
To make them override your present chipset drivers I always used to make a shortcut of the setup file and go to properties and add to the path: "....exe" -OVERRIDE
Then start the shortcut as administrator by right-clicking it.
Please try it and confirm if it works for you or not.