I have had the same issue, update would download, attempt install, fail download and loop.
solution was to manually download the 700+ mb update and install. reboot, open settings updates, and it will say it needs to reboot.
so reboot again and everything was installed.
You can find the update here:
http://www.catalog.update.microsoft.com/Search.aspx?q=KB4088776
edit. i guess anyone else should check if you have version 1709 installed by typing 'system information' in start, open up its the second from top.
Thank You ... you would think the idiots at Microsoft would pay more attention to their customers and offer a quick, easy to find solution.... but NO, hence, Google and Apple and Linux are eating their breakfast, lunch and dinner ... fu Bill Gate and Dalmer ds and your parade of monkeys ... YOU ALL have wasted FAR TOO MUCH OF MY TIME trying to fix the **** you shovel...