Fix NS_E_WMP_PLUGINDLL_NOTFOUND (0XC00D0FD9) in WMP

1. Uninstall the broken codec pack

The culprit here is almost always a third-party codec pack — especially K-Lite, Combined Community Codec Pack, or Shark007. These packs sometimes install a plug-in DLL that gets removed during an update or conflicts with another app. When WMP tries to load that DLL at startup, it throws 0XC00D0FD9.

1. Press Win + R, type appwiz.cpl, hit Enter.
2. Look for any codec packs in the list. Common ones: K-Lite Codec Pack, CCCP, Shark007 Codecs.
3. Right-click and select Uninstall. Restart your PC.
4. Open WMP again. If the error's gone, you're done.

If you need the codec pack later, reinstall the latest stable version from the official site. Don't grab it from some random download mirror — those often bundle junk.

2. Reset Windows Media Player settings

If uninstalling the codec pack didn't fix it, WMP's settings are probably corrupted. This happens when a plug-in fails to register properly. Resetting clears the plug-in list and forces WMP to rebuild it.

1. Close WMP completely.
2. Press Win + R, type regedit, hit Enter.
3. Navigate to:

   HKEY_CURRENT_USER\Software\Microsoft\MediaPlayer\Preferences

4. Right-click the Preferences key and select Delete. Confirm when prompted.
5. Close Regedit, then restart WMP. It'll create a fresh Preferences key.

Don't bother deleting the entire MediaPlayer key — that nukes your library and playlists. Stick to the Preferences key. This fix works on Windows 10 and 11.

3. Re-register the plug-in DLL

Sometimes the DLL is still on disk but its registration is busted. This happens after a Windows update or a partial uninstall. You'll need the exact filename of the missing plug-in from the error details. Open the Event Viewer (search for it in Start), look under Windows Logs > Application for an error from WMP. The Event ID might be 1000 or 1001. The error message should mention the missing DLL name — something like foo.ax or bar.dll.

Once you have the filename:

1. Press Win + R, type cmd, press Ctrl+Shift+Enter to run as admin.
2. Navigate to the folder containing the DLL — usually C:\Windows\System32\ or C:\Program Files\Windows Media Player\.
3. Run:

   regsvr32 filename.dll

   Replace filename.dll with the actual name.
4. You should get a success message. Restart WMP.

If the DLL is missing completely, search for it on a clean PC and copy it over, then register it. But honestly, if a codec pack is this broken, it's faster to just remove it.

4. Run the Windows Media Player troubleshooter

Yeah, I know — built-in troubleshooters are usually useless. But the WMP-specific one actually does one thing right: it resets the plug-in cache and re-registers known libraries. Worth a shot if you're stuck.

1. Go to Settings > Update & Security > Troubleshoot > Additional troubleshooters (Windows 10) or Settings > System > Troubleshoot > Other troubleshooters (Windows 11).
2. Find Windows Media Player in the list, click Run the troubleshooter.
3. Follow the prompts. It'll likely find and clear the corrupted plug-in entry.

This won't fix a missing DLL from a codec pack, but it's a clean 30-second try that can save you digging through the registry.

Quick-reference summary

Start with step one. Nine times out of ten, you just need to ditch a borked codec pack and move on. If none of these work, you might be dealing with a deeper system corruption — consider a repair install of Windows. But I've never had to go that far with this particular error.