NS_E_WMP_ALREADY_IN_USE (0XC00D119E) Fix

What Triggers This Error

You're trying to open a video or audio file, and Windows Media Player either doesn't launch or shows a dialog saying it's already in use. The exact error code you see in Event Viewer or the application log is 0XC00D119E, which maps to NS_E_WMP_ALREADY_IN_USE.

This happens most often right after WMP crashes—maybe you force-closed it with Task Manager, or a video file caused the player to freeze and you killed it. The underlying process doesn't get cleaned up properly. It can also show up if you have multiple media apps fighting for the same audio device, but that's less common.

What's Actually Happening

Windows Media Player uses a background service called wmpshare.exe (for library sharing) and, more importantly, a stub process that keeps a lock on the audio device or the player's internal state. When WMP crashes, this lock doesn't release. The player checks for an existing instance at startup—it sees the orphaned process and assumes you already have it open. Hence the error.

The fix is straightforward: kill the stray process and, if needed, restart the Windows Media Player Network Sharing Service. That's it.

The Fix (3 Steps)

1. Open Task Manager. Hit Ctrl+Shift+Esc or right-click the taskbar and pick Task Manager.
2. Find and kill the hung process. Click the Details tab (Windows 10/11) or Processes tab (older versions). Look for wmplayer.exe or wmpshare.exe. Right-click and choose End task. If you don't see them, check the Background processes section—they can hide there.
3. Restart the service (if the error persists). Press Win+R, type services.msc, and hit Enter. Scroll down to Windows Media Player Network Sharing Service. Right-click it and choose Restart. If it's stopped, start it.

Now try opening your media file again. It should work immediately.

Still Failing? Check These

If the error comes back, something is repeatedly spawning the process. Common culprits:

• Bad shell extension or codec pack. Some older codec packs (like K-Lite from 2010) inject into WMP and cause crashes. Uninstall any third-party codec packs and see if the error stops.
• Corrupt media library database. Close WMP entirely. Navigate to %LOCALAPPDATA%\Microsoft\Media Player and delete the *.wmdb files. WMP will rebuild them on next launch. This clears corrupted cached metadata that might trigger the lock.
• Multiple WMP instances via shortcuts. If you have media files associated with different versions (e.g., WMP12 on Windows 7 and a legacy WMP6.4), they can conflict. Check default programs and set WMP12 as the handler for your file types.

One more thing: if you're on Windows 10 or 11 and WMP keeps crashing, consider switching to VLC or MPC-HC. They handle more formats and don't have this lock-up issue. But if you need WMP for legacy compatibility, the steps above will get you through.