I was fresh installing a new computer with the latest Windows 10 build When I encountered this error.
The computer restarted unexpectedly or encountered an unexpected error. Windows installation cannot proceed.
Clicking OK doesn’t do anything. It restarts the computer and ends up at the same place. What else can I do other than starting the installation all over again?
Let’s give it a try this.
First, press Shift + F10 on your computer when you see the message popping up to open a command prompt window.
Then enter regedit and press Enter to start the Registry Editor.
Navigate to the following key
HKEY_LOCAL_MACHINE\SYSTEM\Setup\Status\ChildCompletion
And change the setup.exe value from 1 to 3.
Once done, close the Registry Editor and command prompt, and click OK to restart the computer.
If everything goes as planned, you should be able to bypass the Install Window error and carry on the process.
At least, this worked for me the other day and I hope it will help you as well if you encountered the same error.