Forum Discussion
Windows 10 clients does not download 2004 (1909) Upgrade from 2016 WSUS Server
Have you try steps from the documentation:
https://docs.microsoft.com/en-us/windows/deployment/update/windows-update-resources
Also, on this page you can find details description of the error you have
buzelac Thank you for showing me the usual WSUS problem solving things, but this one is not anything like in those docs. This problem is specific to the weird mechanism when the client tries to download the update from the server, but only the half of the files does it download from there. The windowsupdatebox.exe is downloaded nicely from it's location, but it tries to download the biggest part (the .esd file with its few GB) from the MS update servers, not from my WSUS server.
Anyway, my clients started to download the esd file as well after a few weeks without changing anything. Maybe one of the other updates did fixed the problem, don't know.