NS_E_DRM_DEVICE_ALREADY_REGISTERED (0XC00D28AB) — quick fix

30-second fix — deauthorize the device manually

This error pops up when you try to register a device that's already tied to your Media Player library. The culprit is almost always a leftover registry entry or a stale authorization token. Here's the quickest way out:

1. Open Windows Media Player (WMP). If you're on Windows 10 or 11, use the legacy version — search for "Windows Media Player" in the Start menu.
2. Click the Library tab at the top left.
3. Under Other Libraries, find your device name. Right-click it and choose Remove from Library.
4. Now go to Tools > Options (if you don't see Tools, press Alt to show the menu bar).
5. Click the Devices tab. Select the device and hit Remove.
6. Close WMP, restart it, and try playing DRM content again.

That clears the stale registration in about 30 seconds. If the error comes back, move to the next step.

5-minute fix — reset the DRM store

Didn't work? The DRM store itself might be corrupted. I've seen this after Windows updates or account switches. Resetting it is safe — you'll just have to re-authorize your devices.

1. Close Windows Media Player and any apps using DRM (like Netflix or Amazon Music).
2. Press Windows + R, type %windir%\ServiceProfiles\LocalService\AppData\Local\Microsoft\DRM, and hit Enter.
3. Delete everything in that folder. Yes, everything. Don't worry — Windows will rebuild it.
4. Open Windows Media Player again. It'll look like a fresh install. Go through the setup wizard.
5. Try playing the DRM file. You'll probably see a prompt to register the device — accept it.

This clears out any corrupted DRM data. Nine times out of ten, this is the fix. If it still fails, we go nuclear.

15+ minute fix — re-register Windows Media Player as a whole

Sometimes the DRM store isn't the issue — the Media Player component itself is. This happens after system file corruption or a botched Windows update. Here's how to force a re-registration:

1. Open Command Prompt as administrator. Right-click Start, choose Command Prompt (Admin) or Terminal (Admin).
2. Run this command to unregister WMP:

   unregmp2.exe /UnRegister

3. Then re-register it:

   unregmp2.exe /Register

4. Now restart the DRM service. Run:

   net stop Audiosrv && net start Audiosrv

5. If you're still stuck, try a System File Checker scan:

   sfc /scannow

6. Reboot your machine, open WMP, and test.

This re-registers every DLL and COM component that WMP relies on. I've had to do this on about a dozen machines after failed Windows 10 feature updates. It's overkill for most people, but it works when nothing else will.

Why this happens in the first place

The error 0XC00D28AB means Windows Media Player thinks the device is already registered in its DRM database. Real-world triggers:

• You reinstalled Windows Media Player or moved to a new user account.
• A Windows update changed the DRM service behavior.
• You used a portable media device earlier and it left a stale entry.
• You tried to sync DRM content to a device that was previously registered under a different account.

I've seen this most often after people upgrade from Windows 10 to 11 and try to play purchased music from the Windows Media Player library. The fix is almost always the DRM store reset in step 2.

One more thing — don't bother with third-party DRM cleaners

There are tools out there that claim to "fix DRM errors" by wiping registry keys. Skip them. They're snake oil. The three methods above cover everything you need. If none work, your DRM file itself may be corrupt — try re-downloading it from the source.