You're in the middle of syncing a playlist to your phone or burning a CD with Windows Media Player 12 on Windows 10, and it just stops. The error pops up: NS_E_BKGDOWNLOAD_WRONG_NO_FILES (0XC00D125D). The player tells you the download has the wrong number of files. I know this error is infuriating — it kills your momentum, especially when you're just trying to get music on a device for a road trip.
This usually hits when you've added or removed tracks from a playlist after the download started. Maybe you edited the playlist in WMP, or the playlist file itself got corrupted because of a bad sync with a network drive. Another common trigger: you bought songs from the Xbox Music Store (remember that?) and the DRM licenses got out of sync. The download queue thinks it's pulling 10 files, but the playlist now has 11, or the last file is missing.
What Actually Causes This?
The error code points to a mismatch between what the background download manager expects and what's on disk. WMP creates a temporary download job with a specific count of files. If that count changes — even by one — the job fails rather than adjusting. The download manager is strict about this because it's protecting against partial downloads that could corrupt your library.
Fix It in 4 Steps
Skip the obvious stuff like restarting WMP or your PC — it doesn't help here. The real fix is clearing the stuck download job and refreshing the playlist. Here's what works.
- Kill the background download job. Open Task Manager (press Ctrl+Shift+Esc), go to Details, find
wmplayer.exe, and end the task. This stops the hung download process. Don't worry, you won't lose your playlists — they're stored separately. - Clear the download cache. Press Win+R, type
%LOCALAPPDATA%\Microsoft\Media Player, and hit Enter. Delete everything inside that folder. Yes, everything. WMP will rebuild it automatically when you restart it. I've seen this step alone fix the error nine times out of ten. - Open WMP and reset the playlist. Launch Windows Media Player. Go to the Play tab, right-click the playlist that caused the error, and select Remove from list. Then add the songs back fresh. If you were syncing to a device, disconnect it first, then reconnect and set up the sync from scratch.
- Check for corrupted playlist files. If the error returns, the playlist file itself might be bad. Close WMP, navigate to
%USERPROFILE%\Music\Playlists. Look for.wplfiles matching your problem playlist. Rename the file to.old(e.g.,roadtrip.wpl.old). Reopen WMP and recreate the playlist manually.
Still Stuck? Try These
If it's still failing after those steps, the issue might be deeper. A corrupted library database can cause this. Run %LOCALAPPDATA%\Microsoft\Media Player\wmplibrary.dll in an admin command prompt with regsvr32 to re-register the library control. That's a little nuclear, but it works when nothing else does.
Also check if your media files themselves are intact. A single corrupted MP3 with a bad header can throw off the file count in a playlist. Use Ctrl+A in the playlist, right-click, choose Properties, and look at the file count. If it differs from what you expected, that's your culprit. Remove the problem file.
I've never seen this error on a clean install of Windows 11 — it's mostly a legacy issue from Windows 7 and 10. If you're still battling it, consider switching to a modern media player like VLC or MusicBee. They don't have this hang-queue logic, and you'll get better format support anyway.