Fix 0xC00D32D9: No locale name for RFC1766 in Windows Media Player

When this error shows up

You're playing a video or audio file in Windows Media Player (WMP), and suddenly it stops. The error pops up: 0xC00D32D9 with the message "There is no name for the supplied locale id." It usually happens after a Windows update or when you've installed a new language pack. I've seen this on Windows 10 22H2 and Windows 11 23H2, especially if you switch the display language or add a keyboard layout. The file might play fine in VLC or other players, but WMP chokes because it can't match the locale to a language description in its metadata.

Root cause

WMP uses the RFC1766 standard to identify languages by a six-letter code (like en-US). When that code doesn't have a friendly name in the system's registry, the error fires. This happens if the matching registry key under HKEY_CLASSES_ROOT\MIME\Database\Rfc1766 is missing or corrupted. It's not a media file problem — it's a Windows configuration issue. The registry holds the mapping between the locale ID (like 0409 for English US) and the human-readable name. If that mapping breaks, WMP throws the error.

Fix it in 3 steps

Step 1: Check your current locale

Hit Win + R, type intl.cpl, and press Enter. Look at the "Format" dropdown — that's your system locale. Write down the region (e.g., "English (United States)"). Now open a Command Prompt as admin and run:

wmic os get locale

You'll see a number like 0409. That's your locale ID in hex. This is what WMP uses to look up the name in the registry. If this looks weird (like all zeros or an unexpected code), you've got a corrupt locale. But don't panic — the real fix is in the next step.

Step 2: Repair the RFC1766 registry key

Open Registry Editor (regedit) as admin. Go to:

HKEY_CLASSES_ROOT\MIME\Database\Rfc1766

Scroll down and find the key that matches your locale ID from step 1. For 0409, it should look like 00000409. If it's not there, you need to create it. Right-click on the Rfc1766 folder, choose New > Key, and name it exactly 00000 followed by your locale ID (e.g., 00000409). Then, inside that new key, create a string value named None (no quotes). Double-click it and set the value to the language name corresponding to your locale:

• For 0409 (English US): en-US
• For 040c (French): fr-FR
• For 0407 (German): de-DE
• For 0809 (English UK): en-GB

If you're not sure, just search online for your locale code. Close regedit.

Step 3: Re-register WMP components

Open an admin Command Prompt. Run each of these commands in order:

regsvr32 jscript.dll
regsvr32 vbscript.dll
regsvr32 wmp.dll

You'll get a success message for each. Then restart Windows Media Player. Try playing that same file. Should work now. If not, reboot — the registry changes take effect after a restart.

What to check if it still fails

If the error persists, two things are usually the culprit:

1. Corrupt language pack. Go to Settings > Time & Language > Language & region. Remove any extra language packs you don't use, then re-add your primary one. This rebuilds the locale mappings.
2. Third-party codecs. Some codec packs (like Shark007 or older K-Lite) meddle with the registry for metadata. Uninstall any recent codec packs, run a system file checker (sfc /scannow), and see if the error goes away.

I've also seen this on Windows 11 after a feature update that didn't carry over the locale registry keys. In that case, the registry fix above is the only reliable workaround. Skip reinstalling WMP — it's tied to Windows Media Feature pack and a reinstall won't fix locale issues.