It's strange that it should affect one install but not the other, although I have two laptops upgraded to Win 10 which both use the same Realtek Ethernet adapter but after the 1709 and 1803 updates, on one of them I will get a Code 45 error on it after a restart and it takes another restart to reinstate it.
One of the subsequent updates after 1709 seemed to resolve but the error has returned with 1803.
I'm hoping the same will happen with subsequent 1803 updates, but not so far.
