vSphere 6 - Fix - Cannot complete operation due to concurrent modification by another operation.

Add more resources to a VM, not a problem right?  Well, not this time.  When attempting to add memory to a VM, I received the following error:

"Cannot complete operation due to concurrent modification by another operation."

I confirmed there were no other operations/modifications occurring on the VM at the same time.  In the past, I would just SSH/Console into the vCSA and restart the services with the following commands.  (Warning - This process is disruptive):

service-control --stop –all

service-control –start –all

In this case, the services restart did not resolve the issue.  On a whim, I created and deleted a snapshot on the VM.  This action "freed" up the VM and allowed me to add the additional resources.

In the future, I'm going start off with the "snapshot" route since it's less disruptive.

Hope this helps!