After upgrading our vCentre server to the latest patch (vCentre 4.1.0-345042), our Update Manager failed to update or even attempt to scan any of our hosts with the error “Host cannot download files from VMware vCenter Update Manager patch store. Check the network connectivity and firewall setup, and check esxupdate logs for details.”

I have searched on the web for the solution to this error and people were mentioning double checking DNS entries on each of the hosts, but that never changed in my case.

I went back to our vCentre server and checked each vCentre server component version installed and it turned out that VUM wasn’t running the latest version. After upgrading and rebooting the machine, ESX host and VM scan and updates were working back again.

Coming from a WSUS era, VUM has provided flexibility and good patch/remediation management for virtual machines until you start seeing this error message “Patch scan or remediation is not supported on ServerName because of unsupported or unknown OS”, this has hit me hard especially moving forward to x64 versions of Windows 2008 R2 and Windows 7.

Vmware has released vSphere compatibility matrix found here. I have taken a snippet of this document shown below:

“Update Manager 4.1 and its subsequent update releases are the last releases of the product to support scanning and remediation of patches for Windows and Linux guest operating systems and applications running inside a virtual machine.” Supported document is found here. Make sure you rethink your patching management and deployment strategies for VM environment, I guess WSUS is still the way to go within Windows environment or purchasing MS System Centre Configuration Manager which makes software updates (not just windows updates) much easier with better control with other capabilities on top.