Any of the following errors are being thrown in vCenter when attempting to remove a VM snapshot created by Veeam Backup Server:
Remove snapshot servername.domain.com An error occurred while communicating with the remote host. AdminUser VCENTERSERVERNAME 16/03/2015 13:40:23 16/03/2015 13:40:23 16/03/2015 13:40:24 Remove all snapshots servername.domain.com The object has already been deleted or has not been completely created AdminUser VCENTERSERVERNAME 16/03/2015 13:39:08 16/03/2015 13:39:08 16/03/2015 13:39:08 Remove all snapshots servername.domain.com The operation is not allowed in the current state. AdminUser VCENTERSERVERNAME 16/03/2015 13:35:57 16/03/2015 13:35:57 16/03/2015 13:35:58
Try restarting the VMware Connector services on the relevant ESX host:
service mgmt-vmware restart
This will show the ESX host as temporarily disconnected from vCenter, don’t panic, its normal.
Once the host returns, manually delete the snapshot via vCenter