NS_E_REMIRRORED_DISK (0XC00D00C9) – Disk Remirrored Fix

You’re looking at this because your disk just told you it’s been remirrored – and that error code 0XC00D00C9 is staring at you like something’s broken.

But here’s the good news: it’s not actually an error. It’s a status message. Annoying? Yes. But not a disaster. Let’s fix it.

Step 1: Confirm the Disk Is Healthy

Open Event Viewer (Eventvwr.msc). Go to Windows Logs > System. Look for the entry with ID 0XC00D00C9. Right-click it and select Event Properties. The description should say something like “Disk %1 is remirrored.” That’s it – no corruption, no failure.

But don’t stop there. Run a quick health check:

1. Open Command Prompt as Administrator.
2. Type wmic diskdrive get status and press Enter.
3. If every drive shows “OK,” you’re golden.

Step 2: Clear the Warning (Optional but Satisfying)

This error doesn’t affect your system, but if you want it gone from Event Viewer, you can clear the log. Back up the log first if you need it for audit. Then:

1. In Event Viewer, right-click System under Windows Logs.
2. Select Clear Log….
3. Choose Save and Clear if you want a backup, or Clear to wipe it.

That’s it. The warning disappears. It won’t come back unless the disk remirrors again.

Why This Happens

This error fires when a disk in a mirrored array (like Storage Spaces, a RAID 1, or a software mirror) finishes rebuilding. It’s a status update that says “hey, I’m done copying data to the other disk.” Microsoft used the same error class for informational messages as they did for real failures – confusing, I know. The 0XC00D00C9 code is from the NS_E namespace, which stands for “Notification Status Error.” So it’s literally a notification dressed up as an error.

I’ve seen this most commonly on Windows Server 2012 R2 and Windows 10 Pro after a drive replacement. For example, you swap a failing 1TB WD Blue for a new 1TB Seagate, and the mirror rebuilds. When it’s done, boom – event 0XC00D00C9.

Less Common Variations

Sometimes the error shows up without a recent remirror. That usually means the disk health check ran and found everything fine – and it just logged the last status. If you see it repeatedly (like every hour), check your Storage Spaces health:

• Open Storage Spaces in Control Panel.
• Look for any drives marked Degraded or Warning.
• If you see a drive with a yellow exclamation, that disk may have intermittent connection issues. Reseat the SATA cable or swap ports.

Another rare case: the error appears after a driver update. I’ve seen it with older Intel RST drivers (version 14.x) on Windows 8.1. Updating to the latest driver (currently 17.x for most systems) stops the false flag.

Prevention

You can’t stop remirrors – they’re how mirroring works. But you can reduce unnecessary rebuilds:

• Don’t hot-swap drives unless you absolutely have to. Every replacement triggers a remirror.
• Use drives from the same batch and model. Mismatched speeds (e.g., 5400 RPM + 7200 RPM) cause the rebuild to take longer, but not the error itself.
• Check your SATA cables annually. Loose or corroded cables cause intermittent disconnects, which trigger false remirror events.

And if you’re on a critical server, don’t ignore the event – at least verify the disk status. But yeah, 9 times out of 10, it’s just noise. You’re safe.