Hi folks,
I recently patched all of my esxi 5.1 hosts and went to do a tools upgrade last night on a couple of VM's. When I try to update via right click and automatic install it simply errors out.

So I decide to go to the console and do an interactive update. It mounts the installer and when I run I get this

The VM in question is running Windows Server 2008R2. It is currently hardware version 7 and I found that if I upgrade virtual hardware sometimes I am able to then install the tools sometimes not.
This is the first time I have seen a minimum virtual hardware version for tools to be updated. Has anyone else seen this and is there a workaround? I have 500+ vms and dont have the ability to shut them all down and upgrade hw.
Thanks!