3 Aug 2011

Cannot install the vCenter Agent Service. Cannot prepare host for upgrade.

While upgrading vCenter, I received the message "Cannot install the vCenter Agent Service. Cannot prepare host for upgrade." when attempting to update the vCenter agent on a standalone ESX 3.02 Host.

To resolve, I connected via SSH and performed the following command to restart the ESX Management Agent.

service mgmt-vmware restart

I then reconnected the Host to vCenter and the agent was updated as intended.