One possible issue after a vSphere 5 upgrade using an in-place upgrade of vCenter Server could appear when you forget to remove the Converter Enterprise plugin (and/or the Guided Consolidation plugin). As you know some products has been removed from vSphere 5, and their plugins may remain in a “orphan” state. The result of this issue is that you will have a “broken” plugins list (with some plugins that are no more available) and also a wrong vCenter health status, due to some services that are no more existing: