The following error is displayed when deleting resources associated with a catalog:
Unable to Delete Resources: There is currently an active background action
There are no provisioning tasks active against the catalog\resource.
There is an entry against the resource\hosting unit in VMInfoPendingDiskDeletes.
To resolve this issue manually delete the entry in the database table.
XenDesktop did not attempt to retry deletion nor raise a flag that entry was still present in the database table.