Hello -
I have been successful in upgrading all vcenter 5.1 components to 5.5 with the exception of the web client. I have a single server with SQL express hosting SSO, vCenter, Update Manager, inventory service and web client (5.1). The upgrade for the web client gets about half way through the install process and then errors out with the below message. I have looked through the logs but can't seem to find a specific reason for the failure. Also I am unable to uninstall the 5.1 web client because it can't find the original web client msi file.