If clients are having trouble downloading and installing updates from your SUS or WSUS server, should check a familiar place—the registry. Go to the problematic client PC and follow these steps:
1. Select Run on the Start menu.
2. In the Run dialog box, type regedit, then click OK.
3. In the registry, navigate to the HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\WUServer subkey. Make sure the WUServer subkey points to your SUS or WSUS server and not Microsoft Windows Update.
4. Navigate to the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update subkey. Find the AUState entry and note its value. The AUState value can help you determine the problem. Here are the possible values and what they mean:
§ 0—initial 24-hour timeout (Automatic Updates doesn't run until 24 hours after it first detects an Internet connection.)
§ 1—waiting for the user to run Automatic Updates
§ 2—detection pending
§ 3—download pending (Automatic Updates is waiting for the user to accept the predownloaded prompt.)
§ 4—download in progress
§ 5—install pending
§ 6—install complete
§ 7—disabled
§ 8—reboot pending (Updates that require a reboot were installed, but the reboot was declined. Automatic Updates won't do anything until this value is cleared and a reboot occurs.)
Force updates detection on a client by following these steps:
1. Stop the Automatic Updates service.
2. Make sure that the Auto Update subkey's AUState value is set to 2.
3. Delete the Auto Update subkey's LastWaitTimeout value.
4. Restart the Automatic update Service.