Problem: In vSphere Web Client 6.0 the ESXi hosts disappear in the left hand navigation, and display the error message:

“ManagedObjectReference: type = HostSystem, value = host-XX, serverGuid = XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXX refers to a managed object that no longer exists or has never existed.” (where the X characters are unique per installation)

vswc-error1

 

Solution: (at least in our case) Upgrade the NetApp VSC plugin application (on its server) to at least version 6.2 Patch 1 (6-2-0-6.2P1), and update the plugin in vSphere Web Client by pushing it from the plugin server.

The patch is available on: http://mysupport.netapp.com/NOW/download/software/vsc_win/6.2P1/ and there is a forum post on http://community.netapp.com/t5/VMware-Solutions-Discussions/ESX-host-disappears-from-vCenter-webclient-inventory-when-VSC-6-1-is-installed/td-p/111726/page/5 that briefly explains the problem and the patch.