I noticed that client machines hadn’t been checking into some of the WSUS servers since the server was upgraded to version 3. Checking the log files of the desktop pc’s had errors such as “Reporter failed to upload events with hr = 80244016”
After a bit of digging and looking at the IIS console, I noticed that the wsus directories were now listening on port 8530 instead of the normal port 80. To fix this I changed the Group Policy setting “Set the intranet update service for detecting updates” and “Set the intranet statistics server” to read http://servername:8530 instead of http://servername, ran gpupdate on the desktop, restarted Automatic Update service, dropped to a command prompt and ran “wuauclt /detectnow” to ensure the desktop checked in *now* rather than later on.