During install of an in place upgrade of vCenter 5.0 Update 1 (build 804276) > Update 2 (build 913577), I had my installation stall at this screen
"Please wait while windows configures vcenter inventory service."
I patiently waited about 45 minutes before doing anything as the server was responding fine.
Went into services and manually started the vCenter Inventory Service.
Once the service started successfully the installation finished without any issues.
Hope this is helpful for someone
