HD How To Fix Windows 10 Update After Reaching 100% Corrupted via WIndows Update. Save your Windows 10 Upgrade Update downloaded through Windows Update on your Windows 8.1 or Windows 7 SP1 platform. This may help recover your corrupted download if it was completed successfully and the update setup moved on from step 100% downloaded to preparing installation.

After downloading Windows 10 and reaching 100%, Windows Update may indicate your download has been corrupted in the midst of the process such as 'Preparing for Installation'. Instead of risking to attempt downloading again by clicking 'Try Again' and starting from scratch, this process may help you the hassle of attempting to re-download the update again saving you both time and your internet bandwidth from downloading 2 GB+ again.

Windows Key + R - To Open Run Command Window
Type 'regedit'
Navigate To Directory: Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\OSUpgrade