You've got a file that Windows Media Player refuses to play, and you're staring at error 0XC00D10C8 — NS_E_WMPCORE_MEDIA_URL_TOO_LONG. It's frustrating, especially when the file plays fine in VLC or MPC-HC. I've seen this happen when you're trying to open a media file buried six folders deep in a network share, or one with a ridiculously long filename.
The fix: shorten the path
Windows Media Player has a hard limit of 2083 characters for the full URL (including the protocol, server, path, and filename). This is a holdover from Internet Explorer's old URL length cap. The quickest way to fix it:
- Move the media file to a shorter path. C:\Music\song.mp3 works. C:\Users\John\Documents\My Music\2024\Summer\Vacation\Beach\Sunset\song.mp3 won't.
- Rename the file to something short.
clip1.mp4beatsMy Summer Vacation Beach Sunset Highlight Reel 2024.mp4. - If it's on a network share, map a drive letter.
Z:\share\video.mkvis shorter than\\server\shared\media\videos\video.mkv.
That's it for 90% of cases. If you're still stuck, read on.
Why does this happen?
What's actually happening here is that Windows Media Player uses the URLMON library under the hood, which inherits Internet Explorer's 2083-character limit for URLs. This limit comes from the maximum length of a string in the Windows shell's INTERNET_MAX_URL_LENGTH constant. The player doesn't truncate or warn you — it just fails with this error.
The reason step 3 works (mapping a drive letter) is that it converts a UNC path (which can be long) to a drive letter (usually much shorter). The player then constructs a URL like file://Z:/share/video.mkv instead of file://server/share/video.mkv. The latter includes the server name in the URL string, eating up characters.
You can't bypass this limit with registry tweaks — it's hardcoded into the URL parsing code. Some old forum posts suggest changing a registry key under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main\UrlEncoding, but that doesn't affect WMP's internal URL handling. Don't waste your time.
Less common variations
Sometimes the error isn't about the file path but the playlist URL. If you're opening an ASX or WPL playlist that references files with absolute paths, each entry's URL must be under the limit. Here's a scenario: you have an ASX file that points to \\server\media\tv\season1\episode1\episode1_part1.wmv. That single reference might be fine, but if the playlist itself has a long path, the file:// URL for the playlist file triggers the error before any media is loaded.
Another variant: streaming URLs with lots of query parameters. Streaming servers sometimes append long authentication tokens. For example: mms://server.com/stream?token=abcdefghijklmnopqrstuvwxyz1234567890&expires=20251231. If the base URL plus parameters exceeds 2083 characters, WMP will throw the same error. The fix is to ask your content provider to shorten the token or use a streaming protocol that handles this better (like RTMP).
Prevention
Keep your media files close to the root of your drive. I organize mine C:\Media\Music\ and C:\Media\Video\. Never nest deeper than three or four directories. For filenames, I stick to Artist - Song.mp3 — no metadata dumps in the filename.
If you're building a media server or sharing over a network, map drives instead of using UNC paths. It's faster, simpler, and avoids this exact headache.
And honestly? If you deal with long paths regularly, switch to a different player. VLC, MPC-HC, or even the modern Windows Media Player Legacy app don't have this 2083-character limit. The old WMP is stuck in 2004's URL constraints. Use it for quick local playback, but don't force it into roles it wasn't built for.