The disk group is critical with at least one inaccessible disk. For example, two disks are inaccessible in a RAID 6 disk group or one disk is inaccessible for other fault-tolerant RAID levels. If the inaccessible disks come online or if after 60 seconds from being quarantined the disk group is QTCRor QTDN, the disk group is automatically dequarantined.