95% of all articles on Internet describe how to resolve this issue. My solution was to uninstall it. Remove WSUS server from ISS. Delete all folders where data stored for WSUS.
While installation you will need to install also .NET 3.5 (it also include .NET 2.0) as version 4 will be installed. The path where everything will be stored need to be shared folder with proper access level, you will need to create it, while WSUS relo installation. Also will be good to install Download Microsoft Report Viewer 2008 SP1 Redistributable from Official Microsoft Download Center (feedback to .NET) link >> https://www.microsoft.com/en-us/download/details.aspx?id=3841
I hope this will help you with Windows patching.