vCenter 6.5 upgrade: A problem occurred while - Starting VMware vCenter Server...

After an initial failed attempt at migrating a Windows based vCenter 5.5 to vCSA 6.5, I received the following error during the subsequent retry:

A problem occurred while - Starting VMware vCenter Server

The \var\log\firstboot\vpxd_firstboot.ph_xxxxx_stdout.log within the vm-support bundle revealed that a service was already registered in component manager.  

This was  due to a previously failed upgrade attempt:

Make note of the id number in red in the example above.  Launch JXplorer and connect to your PSC.  Details regarding JXplorer can be found here:

http://kenumemoto.blogspot.com/search?q=Jxplorer

Drill down to the following location.  Select the offending service and view the details.  As you can see,  it's incorrectly showing as Version 6.5.

Right-Click on the offending service, then click Delete.   Now restart the upgrade\migration process.