There might be a different cause of your problem.
If you have a particular Wi-Fi PCI-e card attached to your motherboard it will cause the problems you are describing. Unfortunately, this is not the only cause of the update problem. If it is the Wi-Fi card, it is fairly easily resolved.
There are several threads that address this issue.
Link: Win 10 update freezes at 82% complete
answers.microsoft.com/en-us/windows/forum/windows_10-update-winpc/windows-10-update-stuck-at-81/d0384db0-4c3e-4e65-9c19-6f62dc0ccfaa
Link:Windows 10 Update stuck at 81%
answers.microsoft.com/en-us/windows/forum/windows_10-windows_install/my-computer-freezes-every-time-a-windows-10/a6745869-9908-4d90-a14a-cf186f62b4c5
Link: My computer freezes every time a windows 10 upgrade occurs
answers.microsoft.com/en-us/windows/forum/windows_10-update/windows-10-hang-up-at-75/5ae468e5-7843-4f37-8211-cc392ef2763b
Link: Windows 10 hang up at 75%
and more...
What it amounts to is an Anatel Wi-Fi card causes major problems with the Win10 updates since 1607. The easiest workaround is to physically remove the Anatel Wi-Fi card from the computer and then allow the update to run. Just disabling the Wi-Fi card in device manager generally does not allow the update to complete. Nor does disabling or removing the driver. A lot of people have solved their update problem by removing the Wi-Fi card physically from the computer.
A lot of people have reported this problem with Acer / Gateway computers but it has been reported on HPs, Asus, and many others. People have reported the device manager identifies it as everything from Ralink, Realtec, Asus, and others. In my case Device manager identified it as Realtec. After I pulled it out, I saw an Anatel manufacturer sticker on it.
I have been able to get past two more Major version updates since removing my Anatel wi-fi card on a 7-year-old Gateway. I do not know if this will help you. I'm just another very frustrated Win10 customer. I am currently on Win10 1803 (originally a Win 7). Removing the Anatel Wi-Fi card allowed me to update to this point.
remaker (the person who originally identified the problem) has posted:
Pull out the PCIe Wireless card and run the update again. Wireless cards based on the RT3090 PCIe wireless card hang every Windows Update since the Creators update, including the Fall Creators Update and the April 2018 update. (1703, 1709, 1804)
Please read through those threads to see if it might apply to your circumstance.
I know this is odd and it seems like none of the normal answers that are constantly given say that a Wi-Fi card will cause this problem. But lots of people have solved there update issues by simply removing their Wi-Fi card from the computer and then letting the update run.
I hope this information helps. Let us know if you get things working.