When attempting to delete an empty cluster object from the vCenter Server inventory, the following error message is received:
The operation is not allowed in the current state. Cluster destroy is not allowed on <Cluster Name>...There can be varying causes preventing the deletion of an empty cluster object, which will be stated in the error message that is received when attempting to perform the delete operation.
If you are unable to temporarily add a host to the cluster or disabling vSAN on the cluster does not resolve the issue then please open a case with Broadcom Support to troubleshoot the deletion of the cluster object, as there may be specific resolution steps depending on the exact error message that is received.