The virtual machine Summary tab reports the error:
The virtual machine inventory file is damaged or unreadable
In the hostd log, you see entries similar to:
hostd.log:2012-07-10 [FFD6FAC0 info 'Solo'] VM inventory configuration: /etc/vmware/hostd/vmInventory.xml
hostd.log:2012-07-10 [FFD6FAC0 error 'Default'] Failed to load VM inventory: not well-formed (invalid token)
hostd.log:2012-07-10 [FFD6FAC0 info 'ha-eventmgr'] Event 58 : The virtual machine inventory file on host hostname.xxx.com is damaged or unreadable.
hostd.log:2012-07-10 [FFD6FAC0 info 'Solo'] VM inventory configuration: /etc/vmware/hostd/vmInventory.xml
VMware vSphere ESXi
This issue occurs if the vmInventory.xml file is corrupt or damaged.
Warning: Performing a vMotion does not include auto-discovery of existing Virtual Machines registered upon a host.
Placing the host into maintenance mode before following these steps will help to avoid manual re-registration of every Virtual Machine on the host.