Windows Update provides a mechanism to download and install feature and quality updates in Windows 10. Windows Update usually works without a hitch, but sometimes problems can happen, and the update process can get stuck or refuse to install a particular update. Windows 10 comes with a built-in Troubleshooter to help you fix your issues with Windows Update and restart the process. If Windows Update is stuck in installation and download loop with errors, your system may have corrupted Windows Update files. After manually updating your PC, you’ll be able to use Windows Update again.
Source: https://www.bleepingcomputer.com/news/microsoft/how-to-fix-windows-update-problems-in-windows-10/