-102: Failed to execute the search. HRESULT: -2145107941

As you pointed out, this is likely an issue with the proxy setup in your environment. Specifically, I believe this is related to proxy authentication. I know you said that the 3 computers are all configured the same, but if they were exactly the same then they would behave the same. They are not behaving the same, so therefore there must be something different about one of them.

Please review the instructions:

'Scenario 2: The Windows Update Agent on target computers is properly configured to use the corporate proxy, but the proxy requires authentication'

Using BatchPatch with an Enterprise Web Proxy

-Doug

I’m confused by this behavior. You’re saying that you execute a Windows Update action in BatchPatch, but where are you prompted with an authentication window? On the target computer? Is that authentication window from Windows or from custom proxy software?

In any event, the idea here is that if you whitelist the Windows Update domains in your proxy server, then when a computer tries to access those whitelisted sites to download updates, the proxy server will be bypassed altogether and no authentication will be required. If you are prompted somehow for authentication (even if you are able to just click ok without entering credentials), it sounds like something is not setup right. You need to configure the proxy to be bypassed altogether for the Windows Update domains. Currently it sounds like it is not being successfully bypassed.