Help with "Windows 10 installation has failed" at 73% on Windows 8.1 Pro

I noticed no network activity between the time that Windows completed downloading Windows 10 and the time it started trying top download updates. I was too busy looking at that to disconnect right away and disconnected before the Download Updates kicked in, but you would probably be safe disconnecting once it's done downloading Windows 10 and at any point after that until it tells you that it's downloading updates. Since the download updates process would take a while, even if you don't stop it the exact second it starts, you should be able to stop it well before it gets to download anything.

Doing that should get you past the 73% part all the way to 100% and you can stay disconnected until it actually boots up as Windows 10. There will be some intermediate things before it gets there when it says that it's looking for something, but those will time out and it won't hurt to stay disconnected.

When to stop it won't be a big issue, and it's nice to see a thread without any "it didn't work for me" posts.

I tried many things, scannow, DISM, etc. but the secret was in Wayne_723's post and that was to skip the updates. I used the Media Creator to create a USB install and when it got to the point where it asked if I wanted to check for updates I declined. It successfully completed the install on two laptops.

I had the same problem. There is a dialog somewhere at the start of the install process that gives you the option to install Windows 10 without updates. I tried installing again, this time i chose to install Windows 10 without updates. It worked for me. After my computer rebooted, updates started installing automatically anyway. There was a minute when the screen went black, so if that happens to you don't freak out. It will come back on. I hope this works for you.

This worked for me! Thank you so much. For those of you who want to try this method, here is what to look for:

When you are upgrading to Windows 10, one of the first screens that you see is titled "Install Windows 10". This has a paragraph explaining updates. Look below this paragraph for the link (in blue letters): "Change how Windows Setup downloads updates". Click on this link.

This brings up a screen titled "Get update, drivers and optional features." Select the "Not right now" option.

This way you can do the upgrade without first downloading the updates. If the upgrade is successful, then the follow-up updating can take place. In my case this updating began automatically, and it took quite a while, more than one hour.

OMG - this is the fix I have been looking for. My Win 10 Pro upgrade kept failing at the same 73% and I could not figure out why. I updated Win7 as far it would go, searched through install logs for errors and always cam up empty.

Thank you for this easy fix.