Fix NS_E_WMP_UPGRADE_APPLICATION (0xC00D11CC) in Windows

The short version

You're trying to open a video or audio file, and instead you get this message: "Windows Media Player is not installed properly." The error code is 0xC00D11CC. It usually happens after a Windows update or when you've messed with Windows Features.

Here's the fix that works 9 out of 10 times:

1. Press Windows Key + R, type optionalfeatures, hit Enter.
2. Scroll down to Media Features. Expand it.
3. Uncheck Windows Media Player (if checked). Click OK.
4. Restart your PC.
5. Go back to optionalfeatures and check Windows Media Player again.
6. Restart again. That's it.

What's actually happening here is that Windows Media Player's core files got corrupted or half-removed. The toggle in Windows Features forces Windows to fully uninstall and reinstall the component. Doing it twice — off then on — makes sure the registry entries are written fresh.

When the simple fix doesn't work

If the above doesn't help, you've got a deeper problem. Usually it's one of these:

• You're on Windows 10/11 N edition. These versions don't include WMP at all. You need to download the Media Feature Pack from Microsoft's site. Search "Media Feature Pack for Windows 10/11 N" and install it.
• Third-party media software broke the registration. Something like K-Lite Codec Pack or VLC can mess with WMP's DLL files. Open Command Prompt as admin, run regsvr32 wmp.dll and regsvr32 wmpdxm.dll. This re-registers the main WMP libraries. If you get an error, the files are missing completely.
• The WMP folder is gone. Check C:\Program Files\Windows Media Player. If it's empty or missing, Windows is missing the program files. Run sfc /scannow in an admin Command Prompt. That'll restore system files.

Why this error happens

Windows Media Player is a Windows Feature, not a regular program. It's tucked into the OS install. When Windows updates or you uninstall something related (like a codec pack), the feature can get into a broken state. The error code 0xC00D11CC translates to "NS_E_WMP_UPGRADE_APPLICATION" — meaning the component is there but can't load because the installation is incomplete.

The reason step 3 works is that unchecking WMP in Windows Features triggers a proper removal. It deletes the registry keys that point to the old, broken files. Then checking it again installs fresh copies from the Windows image store (the WinSxS folder). No internet needed.

Preventing it from coming back

• Don't manually delete files from Program Files\Windows Media Player. You'll break it.
• If you install codec packs, use Combined Community Codec Pack (CCCP) — it doesn't touch WMP's core files. Avoid K-Lite Mega Pack unless you know what you're doing.
• After a major Windows update (like 22H2 to 23H2), check if WMP still works. If not, run the toggle fix again.
• Set Windows updates to notify you before installing. That way you can test WMP right after an update and rollback if needed.

That's all. No need to dig into the registry or download shady tools. The Windows Features toggle is the only reliable fix.