Follow this KB only if the datastore doesn't exist in the vCenter database. If the datastore is found in the database then it will need to be deleted using this KB -
The vMotion/Creation of VM returning the error: "The object 'vim.Datastore:datastore-xxx' has already been deleted or has not been completely created" (78241)
- Browse to the cluster in the vSphere Client.
- Click Configure.
- Select Configuration > General.
- Next to swap file location, click Edit.
- Select datastore specified by the host
Once applied navigate to the affected ESXi host(s), click on Edit swap file location and configure the VM swap location to a valid datastore
NOTE : this action is temporary to remove the stale entry of the deleted datastore
Once configured to a valid datastore on each host go back to the Cluster setting and change back to "Virtual machine directory"