Quick answer: Reboot, open Disk Management, and look for a failed or missing disk in your RAID or mirrored volume. If it's offline, right-click it and select Reactivate Disk. If that doesn't work, replace the failed physical drive and rebuild the array.
I know this error is infuriating — you turn on your machine and instead of your desktop, you get a blue screen or a boot loop with STATUS_FT_MISSING_MEMBER. This tripped me up the first time too. The code means Windows still sees the volume as part of a fault-tolerant array (mirror or RAID-5), but one of the members is physically missing or electrically dead. It's not a data-loss death sentence — usually. Let's get you back in.
Why does 0XC000015F happen?
Windows marks a disk as a fault-tolerant member when you create a mirrored volume or a RAID-5 set using dynamic disks or Storage Spaces. If that disk doesn't respond during boot — maybe the SATA cable wiggled loose, the drive's firmware didn't spin up in time, or the drive finally gave up — Windows throws this stop code. You'll often see it on Dell PowerEdge servers or custom desktops with two identical drives in a mirror.
Fix steps: Reactivate or rebuild
- Boot into Safe Mode (press F8 during startup on Windows 7/8, or Shift + Restart on Windows 10/11). If you can't get past the error, use a Windows installation USB and choose Repair your computer.
- Open Disk Management — press
Win + R, typediskmgmt.msc, hit Enter. Look for a disk with a red down arrow or the label Missing under the mirrored volume. - Reactivate the disk — right-click the disk's left pane (where it says Disk 1, Disk 2, etc.) and choose Reactivate Disk. This only works if the disk is actually there but Windows lost the connection. If it works, the mirror starts resyncing automatically.
- Check physical connections — if the disk doesn't show up at all, power down, reseat the SATA and power cables, and check if the drive spins up (put your hand on it — you should feel a slight vibration).
- If the disk is dead — replace it with an identical or larger drive. Boot back into Disk Management, right-click the failed mirrored volume, and select Add Mirror. Pick the new disk, and Windows rebuilds the mirror.
Alternative fixes when the main one fails
Sometimes the disk is fine but the partition table is corrupted. Don't panic — you can often salvage it without a rebuild.
- Use DiskPart — open Command Prompt as admin and run
diskpart. Typelist diskto see all disks. If the missing disk appears, select it (select disk 1) and tryattributes disk clear readonly. Then go back to Disk Management and reactivate. - Import foreign discs — if the disk shows as Foreign (common when you move a RAID set from another system), right-click the disk and choose Import Foreign Disks. Windows will merge the metadata.
- Use Storage Spaces instead — if you're on Windows 10/11 and the array keeps dropping, consider rebuilding it as a Storage Space. It handles missing drives more gracefully. I've seen ol' dynamic disks flake out for no reason, and Storage Spaces is the modern way.
- Check the event log — open Event Viewer (
eventvwr.msc) and look for warnings from the Volume Manager or disk sources around the time of the error. It'll often tell you which disk failed and why.
Prevention tip: Don't trust a single mirror
You're already smart for running a mirror, but here's the kicker — if both drives are the same model and same batch, they can die around the same time. I've seen it happen on a client's server: two WD Reds, both failed within a week. Buy drives from different batches, and always keep a verified backup. Also, run chkdsk /f on the volume once a month to catch early corruption.
Pro tip: if you're using dynamic disks, mark the volume as Active only on the system drive. A mirror can't boot if the boot partition isn't marked correctly.
This error is a scary one, but it's usually fixable. Start with reactivation, then check cables, then replace. If you're still stuck after all that, drop a comment with your disk layout — I'll help you sort it out.