I am slowly but surely moving all of the services from Windows SBS 2008 onto our brand new Windows 2016 Server. This article covers the steps I took to decommission WSUS 3 after switching to WSUS 4.
Firstly, I checked that none of my clients were still connecting to WSUS 3. Once I established this, I manually deleted all of the client machines from the Console.
Next, I set “Any” updates I had previously “Approved” to “Not Approved”.
Finally, configure the WSUS server to NOT store updates locally.
At this point, you can run the WSUS Server Cleanup Wizard and you should see a large amount of hard disk space reclaimed. In my case, this was almost 35GB.