Open C:\WUTEMP folder and delete the contents of the folder (If any files exist).
Go to "WindowsUpdate" folder in "Program Files" folder, and delete all the contents except the "V4" folder.
NOTE: "WindowsUpdate" is a hidden folder.
Highlight the "V4" folder, then click Edit from the menu bar at top of the window and choose Invert Selection. If you cannot locate the "V4" folder, please skip this step, and then continue to delete the rest of the files by choosing Select All instead of Invert Selection.
If you see the V4 folder, open it and delete all the contents of it except the "iuhist.xml" file.
Also, delete all the contents of the C:\WUTemp folder.
Once after deleting all the files, you need to unregister the old control. Follow the below mentioned steps:
Click Start, Run.
Type: "regsvr32 /u C:\WINNT\System32\IUCTL.dll" (Without Quotes. You should get an unregistered successfully message.)
Find the old site controls and delete the same. Ensure that you don't have "IUCTL.DLL" and "IUEngine.dll" files located in the system.
Restart Windows and try accessing Windows update..
Article ID: 555461 - Last Review: Feb 14, 2017 - Revision: 1