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

[sysjno]

Our vCenter Server is the appliance, version 6.something.  This is on just one VM.  Googling isn't helping... since vCenter Server is not on a Windows machine, I cannot "restart the service" like pretty much every search result suggests.

How do I clear out this 'concurrent operation" and move forward?

[virtualg_uk · Accepted solution]

You can restart VCSA services via shell: Stopping, starting, or restarting VMware vCenter Server Appliance 6.x services (2109887) | VMware KB

See the last section on that KB article.

Also, you could try to reboot the VCSA to clear out anything that might be causing this?

[SureshKumarMuth]

Check if there is any genuine task running on that virtual machine by taking direct esxi session from vsphere client, check the tasks in progress. If there are any task running on it or stuck in progress you may try to cancel it. If there are no pending task, then its an issue with vcenter server that did not sync properly with the host to update the task status. Restarting the vcenter service would help in that situation.

[sysjno]

Thanks, Graham, that worked like a charm 🙂