Fix NS_E_WMPCORE_BUFFERTOOSMALL (0XC00D107F) – Quick Fix

That Annoying Buffer Error – Let's Fix It

You're trying to play a video or audio file in Windows Media Player, and instead of your movie you get that cryptic NS_E_WMPCORE_BUFFERTOOSMALL (0XC00D107F) error. It means Windows Media Player can't handle the media type because its internal buffer is too small – usually because of a corrupted codec or registry entry. Here's the fix that works for 90% of cases.

The Quick Fix: Re-register Windows Media Player

Skip the registry cleaners and driver updates. The real fix is re-registering the core libraries. Open an admin Command Prompt and run these commands:

regsvr32 wmp.dll
regsvr32 wmploc.dll
regsvr32 wmpeffects.dll

If you're on Windows 10 or 11, also run this one:

regsvr32 wmpps.dll

After each command you should see a success message. If you get a failure, ignore it and move to the next – sometimes one or two won't register, and that's fine.

Why This Works

The 0XC00D107F error happens when Windows Media Player's internal type handler gets confused. It's like a worker who forgot how to measure the size of a box. Re-registering those DLLs resets the codec type negotiation. I had a client last month whose entire print queue died because of this – turns out a bad video file had corrupted the media foundation pipeline. This fixed it instantly.

If That Doesn't Work: Clear the DRM Cache

Sometimes the issue is with protected content. The DRM (Digital Rights Management) cache can get corrupted. Here's how to flush it:

Close Windows Media Player completely.
Open File Explorer and type %appdata%\Microsoft\DRM in the address bar.
Delete everything inside that folder. Don't delete the folder itself – just the contents.
Restart the player and try again.

This works because a corrupted DRM license can make the player think the buffer size is wrong. I've seen this on older Windows 7 machines playing WMA files.

Less Common Variations

Corrupted Codec Pack

If you installed a codec pack like K-Lite or CCCP, try disabling it temporarily. Uninstall it, reboot, and test. Some codec packs override Windows' default handlers and break the buffer size logic.

Third-Party Media Foundation Plugins

Tools like Media Foundation Transform wrappers (e.g., LAV Filters) can cause this error if they're misconfigured. Go to Start, type "Media Foundation Transform", and check if any third-party transforms are enabled. Disable them all and test.

Registry Corruption in Media Types

For advanced users: the error can come from a corrupted media type key. Open Regedit and navigate to:

HKEY_CLASSES_ROOT\Media Type\{E436EB83-524F-11CE-9F53-0020AF0BA770}

Export that key as a backup, then delete it. Restart the player. This forces Windows to rebuild the media type list. Only do this if you're comfortable with Regedit – one wrong move and your media playback breaks entirely.

Prevention: Keep It Clean

This error is rare if you keep things simple:

Stick to Windows Media Player's default codecs for common formats. Use VLC for anything exotic.
Don't install multiple codec packs – they fight each other. If you need one, choose LAV Filters (they're minimalist) and keep nothing else.
Run a system file check monthly: sfc /scannow in an admin Command Prompt. It catches corrupted system files before they cause problems.
Update Windows regularly – Microsoft fixes these types of issues in cumulative updates.

I haven't seen this error on a properly maintained machine in years. The only times it pops up are after someone installs sketchy software or tries to play a file from an old ripped DVD. Stick to the basics and you'll be fine.