I got the following error attempting to check for updates against my WSUS server from a Windows 7 system.
Looking closer at the WindowsUpdate.log file (C:windowsWindowsUpdate.log), I see the following:
2014-07-17 17:10:00:141 936 e28 Agent * Search Scope = {Machine}
2014-07-17 17:10:00:141 936 e28 Setup Checking for agent SelfUpdate
2014-07-17 17:10:00:142 936 e28 Setup Client version: Core: 7.6.7600.256 Aux: 7.6.7600.256
2014-07-17 17:10:00:173 936 e28 Misc Validating signature for C:WindowsSoftwareDistributionSelfUpdatewuident.cab:
2014-07-17 17:10:00:179 936 e28 Misc Microsoft signed: Yes
2014-07-17 17:10:00:179 936 e28 Misc WARNING: Digital Signatures on file C:WindowsSoftwareDistributionSelfUpdatewuident.cab are not trusted: Error 0x800b0001
2014-07-17 17:10:00:180 936 e28 Setup WARNING: SelfUpdate check failed to download package information, error = 0x800B0001
2014-07-17 17:10:00:180 936 e28 Setup FATAL: SelfUpdate check failed, err = 0x800B0001
2014-07-17 17:10:00:180 936 e28 Agent * WARNING: Skipping scan, self-update check returned 0x800B0001
2014-07-17 17:10:00:184 936 e28 Agent * WARNING: Exit code = 0x800B0001
I needed to install KB2720211 on my WSUS server because the client has been updated to the new Windows Update Agent, and the new WUAgent cannot talk to an older WSUS3SP2 server.
