I have an ESX 4.1.0 host, at patch level 348481, that I am trying to remediate, bringing it up to patch level 502767. We are running VSphere 5 with VUM 5.0.0.8039. VCenter Server is at version 5.0.0 as well.
We had recently upgraded all of the hosts but one back in December 2011 with the same patches that I am trying to apply now. This was before upgrading to Vsphere 5 though and vCenter Server 5. These patches worked fine back in December with no issues, and the upgrade to VSphere 5 and VCenter Server 5 was done in February.
When I click remediate, choose the patches, and proceed to start it, it fails right away, with status "VMware vSphere Update Manager had an unknown error. Check the events and log files for details". When I go into the events log under Tasks & Events, I see three items, the first being Task: Remediate entity, then "Scanning Object server.domain.com" then "Could not scan server.domain.com"
If I simply try to do a scan, it fails as well if I have "Patches and Extensions" selected, but if I only have "Upgrades" selected, it finishes and is successful.
I have verified that if I try and do these same actions on one of the hosts that has already been upgraded, it also fails to scan when "Patches and Extensions" is selected, so it isn't just a problem with this one host, but seems to be an issue with VUM.
Any ideas of how I can resolve this issue?