ASROCK P4VM900-SATA2 Installation Manual page 17

RAID 1 array is detected by the RAID software, it will indicate a serial steps to repair this problem.
1. A dialog box will pop up to indicate the RAID is broken. Click Yes.
2. Then another dialog box will pop up. If the source or the mirror disk drive is unplugged only, click "Cancel" to stop rebuilding step. Shut down
the system. Plug the absent disk drive, and then reboot the system. If the original disk drive is broken-down, you may plug a new disk drive
then reboot the system. Click "Next" to the next step.
3. Select a disk drive from "Available Disks" and click button to replace the broken-down one, and then click "Next".
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