WMP error 0xC00D108C: error sink not registered fix

Quick answer: Open Command Prompt as admin and run regsvr32 wmp.dll then regsvr32 wmpdxm.dll. That re-registers the core DLLs Windows Media Player needs to handle errors properly. Reboot after.

You're getting error 0xC00D108C (NS_E_WMPCORE_ERRORSINKNOTREGISTERED) when you try to play a music file or rip a CD in Windows Media Player. The error text says an error sink was never registered for the calling object. In plain English: Windows Media Player can't talk to its own error system. This usually happens after a Windows update overwrites some DLLs, or after you install a codec pack that messes with WMP's registration. I've seen it most often on Windows 10 version 22H2 and Windows 11 after the KB5034441 update. The real fix isn't reinstalling WMP (you can't on modern Windows anyway) — it's fixing the DLL registration.

Fix it: Re-register WMP DLLs

1. Press Win + X and choose Terminal (Admin) or Command Prompt (Admin). If you get a UAC prompt, click Yes.
2. In the black window, type or paste this command exactly, then press Enter:
   

   regsvr32 wmp.dll

   After you press Enter, you should see a popup that says DllRegisterServer in wmp.dll succeeded. If you see an error like The module failed to load, make sure you're running as admin.
3. Next, run this command:
   

   regsvr32 wmpdxm.dll

   Again, you should get the success popup.
4. Now run these two commands in the same order — one at a time, pressing Enter after each:
   

   regsvr32 wmpcm.dll
   regsvr32 wmpui.dll

   Each should show the same success message.
5. Close the Command Prompt window and restart your computer. This step matters — the changes don't fully take effect until Windows reloads the media framework on boot.
6. After restart, open Windows Media Player and try to play a file. The error should be gone.

If the error persists

Sometimes the DLLs are missing or corrupted, not just unregistered. Here's the backup plan:

1. Open Command Prompt as admin again (same steps as above).
2. Run the System File Checker:
   

   sfc /scannow

   This takes 15-20 minutes. Let it finish. It'll replace any damaged system files, including WMP DLLs.
3. After SFC completes, run this command to check for disk errors:
   

   chkdsk /f

   You'll get a message saying the drive is in use and asking if you want to schedule it for next restart. Type Y and press Enter, then restart your PC. The scan runs before Windows loads.
4. After chkdsk finishes and Windows boots, run the four regsvr32 commands from the main fix again.

Another angle — reset the Media Player app

If you're on Windows 11 and using the new Media Player (not the classic WMP), try this instead:

1. Open Settings (Win + I).
2. Go to Apps > Installed apps.
3. Search for Media Player.
4. Click the three dots next to it, choose Advanced options.
5. Scroll down and click Repair. Wait for it to finish. If that doesn't work, click Reset (this deletes your library data but fixes the app).

Why this happens — and how to avoid it

The most common trigger? A Windows Update that includes a new version of Windows Media Feature Pack, especially on Windows 10 N or KN editions. Those editions are missing media features by design, and when you install the feature pack later, it can mess up DLL registration. Also, if you've ever installed a codec pack like K-Lite or Combined Community Codec Pack, they sometimes unregister WMP's DLLs to make room for their own filters. After you uninstall those codec packs, the original DLLs stay unregistered.

To prevent this going forward: if you install codec packs, use the default installation options unless you really know what you're doing. And always create a system restore point before applying Windows feature updates — that way you can roll back if WMP breaks. I've seen too many people lose hours to this error because they didn't have a restore point.

One more thing: If you use a third-party media player like VLC or MPC-HC as your default, you might never notice this error. But if you need Windows Media Player for specific formats (like DRM-protected WMA files from old music purchases), you've got to keep those DLLs registered. And honestly, for DRM content, there's no good alternative — WMP is the only player that handles it properly.