how to clear windows update cache

Delete C:\Windows\SoftwareDistribution and C:\$WINDOWS.~BT folders. Since some files may be in use, I sometimes boot from Windows 10 install media (such as a bootable USB stick) and use SHIFT-F10 to get a Command Prompt. Then:

rd /S /Q C:\Windows\SoftwareDistribution

rd /S /Q C:\$WINDOWS.~BT

If you are having issues related to Windows Updates in Windows 10 operating system then clearing Windows update cache will perfectly help you in solving Windows update errors (Windows Update Stuck at Checking for Updates, Windows Update Stuck at preparing to install updates, or Windows Updates Stuck at 0%) in Windows 10 PC. 

In order to clear Windows Update cache in Windows 10 / 8 / 7:

• Press Win + R and then type services.msc and hit Enter.
• Find and double click on Windows Update and then click on Stop button.

• To delete Update cache, go to - C:\Windows\SoftwareDistribution\Download folder.
• Press CTRL+A and press Delete to remove all files and folders.

• Again press Win + R and then type services.msc and hit Enter.
  
• Find and double click on Windows Update and then click on Start button.

In case the old downloaded Windows updates were corrupted on your system, this action would get a fresh download of the update and try installing again.

Article and image source: http://www.zerodollartips.com/clear-windows-update-cache/

I hope it helps.

Thanks