NEC Express 5800/320Lc - Manual (Page 100)

3-26 Windows Setup and Operation
4. Right-click a volume that has “!”, and
remove mirror.
5. After checking to see the “Missing”
disk is selected, click [Remove
mirror]. At Drive (F), [Mirror] and
[Failed Redundant] will change to
[Simple] and [Healthy].
6. Right-click a disk with “x”, and select
[Remove Disk].