How to fix Windows 11 update stuck at 0%, 61%, 99%, 100%

• Turn off Windows Update and Background Intelligent Transfer Service
• Open the Start menu search, type “cmd”, and then select the “Run as administrator” option to launch an elevated Command Prompt.
• Execute the command net stop wuauserv and net stop bits in order.
• Close Command prompt
• Delete the update files in the SoftwareDistribution folder
• Navigate to C:\Windows\SoftwareDistribution and select all the files and folders there.
• Right-click on the selected items and select Delete. If you fail to delete them, restart your computer and try again.
• Turn on the services again
• Launch Command Prompt in Admin mode. 
• Run the command net start wuauserv and net start bits one by one.
• Exit Command Prompt.

Setup TFT Server on Windows

• Download and install the free TFTP Server from SolarWind
• Configure the server 
• Push file to tftp server: tftp -i localhost put d:\123.img
• Pull file from tftp server: tftp -i localhost get 123.img d:\123.img
• Default tftp file location on disk: C:\TFTP-Root
• Visit here for more info

Find the Windows Product Key

PowerShell
powershell "(Get-WmiObject -query 'select * from SoftwareLicensingService').OA3xOriginalProductKey"

Command Prompt

wmic path softwareLicensingService get OA3xOriginalProductKey

Registry

Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SoftwareProtectionPlatform