Deleted datastore remains with a status of "inactive"
We recently decommissioned an ESXi host in the environment. However, the local datastore to that host still remains in the "Datastores and Datastore Cluster" view (albeit greyed out). The reason for this is because there may still be a VM that is mounting an ISO from that datastore. Simply click the VM tab under that datastore and check the settings for the VMs that show up. Once the ISO is unmounted, the inactive datastore will disappear.