We just update the latest patch on an ESX 4.0 Host.
When it reboots, it stops at the stage "Waiting for Inventory Collector to Finish". Is it a VC issue or an ESX host one ?
It appears it is a problem related to OpenManage Agent.
Finally, we find that we have to upgrade BIOS to 2.6.1 (PowerEdge 2950 Server) and use OpenManage 6.1 (OpenManage 5.5 doesn't work properly).