I am another victim of the 1803 update. About ready to lose my mind! Have done it on 2 PC's from 1709 without issue but a BRAND NEW out of the box Dell Laptop I am helping a guy setup it just does not get along with it. I have tried 3 times now, and it takes all day to do it on this as well, and each time it does update but then performance goes in the tank and it takes about 20 minutes to boot. Get a black screen after the login screen for about 19 minutes of that. Usually the desktop eventually appears but not always. Just had it. Rolling back to 1709 and disabling any more updates. My Sister had it brick her laptop and work PC.