Googling the issue seems to point to this problem not being very rare. There are a few suggestions in the following Microsoft thread, but it appears that it may be related to add on cards, and in particular WLAN cards, or possibly the drivers associated with these WLAN cards.
Depending on how much data you have available to you, or if you could do it late at night if you have at least 4GB of Bonus Zone data available to you (it's takes less than 4GB, but more than 3GB), you may be able to download the Windows 10 1709 ISO, and either immediately update your current system, or write the ISO to a DVD or flash drive and install it that way. You have to use the Media Creation Tool to download the ISO, but this may work better for you, though it takes more data to do so as you are downloading the entire Windows 10 1709 Operating System installation rather than just the update components. But, if you can't get the update to work, this may be a viable option for you. I download each version of the Windows 10 ISO and write them to DVD just to have them on hand if I need to reinstall later. And because your computer already has Windows 10 installed on it and its activation is noted and saved on Microsoft's servers, the new installation will automatically activate.
Here's the address for the Media Creation Tool for Windows 10 1709. It doesn't specify that it's 1709, but the tool always download the latest release, which is 1709. Make sure to read all pertinent instructions about downloading and installing the OS. Keep in mind that if you do end up installing the OS this way, you will have to reinstall any programs or apps that you have currently on your computer, and make sure to save all things that you want to keep before you perform an installation, as you can lose those things when doing so.
Hope this helps.
The recommendation from GabeU to use the ISO method is one of the better methods to get past this problem. In the thread linked I did find someone who provided a solution, granted the majority of the users having the issue all owned the same computer make (Gateway). After the solution is provided it appears the next three pages are people saying that their problem was solved. Hopefully this is the case for you as well:
I was having a similar problem, and after multiple attempts (over 7 times) trying different solutions like disabling virus protection, disabling startup programs, running update database corruption repair, etc. My computer never got past 81% before freezing and not updating.
I stumbled across a forum talking about problems with Anatel PCI-E Wlan cards (wi-fi) and old drivers that would hang up their computers and after removing the card (not just disabling) their machines would update and run fine. Since I was running my machine through an Ethernet connection, connected to an access point, I could remove the Anatel card in my computer and still have an internet connection. I tried it, and my computer a Gateway FX6860 updated to Windows 10 Fall Creators version without any problems.
Check to see if you have an Anatel wifi card and remove it and replace it with something newer or an Ethernet or usb connection to the internet and try the update. this worked for me.
I took out the Anatel Wi-Fi card and tried the updates again and they WORKED.
Let us know if any of this works for you.
It's been a while since we've heard from you so we will go ahead and close this thread. If you have any other questions or concerns please feel free to create a new thread!