During upgrade from any existing supported version OR un installation of windows based vCenter fails with following error.

VMware Message Bus Configuration service failed stop.
Couldn't install the message bus configuration service, due to the following reason: traceback
File \Program Files\VMware\vCenter Server\Firstboot\mbcs_firstboot.py. Line 276.
..
..
The directory is not empty

vCenter_upgrade_failed

This issue comes because stale directory known as tomcat.8080 create at various location inside vCenter server that cause upgrade, reinstallation and various different vCenter operation.

To solve this issue, open vCenter installation directory and search tomcat.8080

Typical location of this directory

\Program Files\VMware\vCenter Server\mbcs\tomcat.8080
\Program Files\VMware\vCenter Server\vmon\tomcat.8080
\Program Files\VMware\vCenter Server\vsm\wrapper\tomcat.8080

Take backup of all these directory and delete.

Attempt to upgrade/uninstall vCenter that stuck due to this error.