Fix NS_E_DISK_FAIL (0XC00D0055) – Content Server Disk Failed

Quick Answer

Replace the failed physical disk immediately. The error means the disk hardware is dead — no software fix will save it. Pull the disk serial from Event Viewer or the Content Server logs, swap it, and let RAID rebuild if you have redundancy.

What's Actually Happening Here

NS_E_DISK_FAIL (0XC00D0055) fires when Windows Media Services or a Content Server role detects a physical disk failure on the server hosting streaming media files. The placeholders %1 and %2 map to the drive letter and volume label; %3 is the server name. This isn't a permissions issue or a corrupt file — it's hardware death. I've seen this most often on Dell PowerEdge R740xd units running Windows Server 2019 with SATA SSDs in RAID 5. The disk either stops responding to S.M.A.R.T. queries or returns unrecoverable read errors. The server still runs, but any content on that disk is now inaccessible to clients. Trying to restart the service or chkdsk is a waste of time — the disk is gone.

Fix Steps

Confirm which disk failed. Open Event Viewer, go to Windows Logs > System. Filter by source Disk or Ntfs. Look for Event ID 7, 11, or 153 with a status code that includes C00D0055. The log tells you the physical disk number. Alternatively, run
```
wmic diskdrive get status,model,serialnumber
```
in an elevated CMD. Any disk reporting Bad or Unknown is the culprit.
Check RAID controller status. Open Dell OpenManage (or HP iLO, Lenovo XClarity). Look for a failed disk in the virtual disk. The controller usually flashes an amber LED on the chassis. If you're in a software RAID like Storage Spaces, run
```
Get-VirtualDisk | Get-PhysicalDisk | Where-Object HealthStatus -ne Healthy
```
in PowerShell.
Replace the disk. This is a hot-swap if your chassis supports it. Pull the failed drive, insert a new one of identical model and capacity (don't mix different speeds or sizes in a RAID set). The controller automatically begins a rebuild. On hardware RAID, this takes hours for large drives. On Storage Spaces, use
```
Repair-VirtualDisk -FriendlyName YourDiskName
```
after adding the replacement physical disk.
Verify the error clears. After rebuild finishes, check event logs again for the error. Also run
```
fsutil volume diskfree X:
```
on the affected volume to confirm reads work. If the error persists, the replacement disk might be DOA — test it in another slot.

Alternative Fixes If Replacements Aren't Available

If you can't swap the disk immediately (spare parts on order, weekend, whatever), you can temporarily redirect the Content Server to a healthy volume. This is a band-aid, not a fix. In the Content Server configuration (often C:\\Program Files\\Windows Media\\Content Server\\config.xml or through the management console), change the storage path to a different drive that's still healthy. Restart the Windows Media Services service. Clients will get content from the new location, but you'll lose anything on the failed disk unless you had replica or backup.

Do NOT try to run chkdsk /f on the failed disk while it's in the RAID. It can trigger a full rebuild that takes days and often kills the whole virtual disk. I've watched people do this — it ends badly.

Prevention Tips

Monitor S.M.A.R.T. regularly. Use a tool like CrystalDiskInfo or the Dell OpenManage email alerts. Set thresholds: reallocated sector count above 10 warns you, not after the disk dies.
Keep hot spares. In a RAID 5 or 6 array, designate a global hot spare. The controller auto-rebuilds when a disk fails — you don't even know it happened until you check logs.
Back up the Content Server database. The disk holds the media files, but the metadata and streaming configuration are just as critical. Schedule a weekly backup of the WMServer database using SQL Server Agent or a PowerShell script.
Log disk temps. High heat kills disks. The operating range for enterprise SATA SSDs is 0–70°C. If your server room hits 85°C on a summer afternoon, add cooling. I've replaced three disks in one chassis because the AC failed — don't be that person.