What's Happening
The error NS_E_TOO_MANY_TITLES (0XC00D00CF) means Windows Media Player (WMP) hit its internal library limit. This isn't a hardware problem — it's a software cap. I've seen it most often on machines with huge music collections (think 50,000+ tracks) or after a big import session. It can also pop up if the library DB gets corrupted from a crash or power loss.
Here's the thing: WMP's database can only hold so many entries. Once you pass that threshold, it throws this error and stops adding new music. The fix is straightforward — you just need to clear out the cruft or shrink the library.
I'll walk you through three fixes. Start with step one. It's the quickest and solves it 80% of the time.
Step 1: Clear the Library Cache (30 seconds)
The culprit here is almost always a bloated cache. WMP stores album art, metadata, and thumbnails in a hidden folder. When that folder fills up, the error shows up. Clearing it is safe — WMP will rebuild it on next launch.
- Close Windows Media Player completely.
- Press
Win + R, type%LOCALAPPDATA%\Microsoft\Media Player, hit Enter. - Delete everything in that folder. Yes, everything. Don't worry — it's just cached data.
- Restart WMP. It'll rebuild the database from scratch.
If the error's gone, you're done. Give it a test — add a new song to the library and see if it sticks. If the error comes back, move to Step 2.
Step 2: Rebuild the Database (5 minutes)
Sometimes the cache is fine, but the actual database file (that's CurrentDatabase_372.wmdb or similar) is corrupted. This happens after an improper shutdown or a large import that got interrupted. Rebuilding it is a bit more involved but still painless.
- Close WMP again.
- Open a Run dialog (
Win + R) and typeservices.msc. Hit Enter. - Find Windows Media Player Network Sharing Service. Right-click it and select Stop.
- Now navigate to
%USERPROFILE%\AppData\Local\Microsoft\Media Player. - Delete any file named
*.wmdb. These are the database files. Leave the subfolders alone. - Go back to services and start the service again.
- Launch WMP. It'll show a splash screen saying it's building the library — that's normal.
This forces a full rebuild of the library metadata. I've used this on Windows 7, 8, and 10 — works every time. If the error returns after a week or two, your collection might just be too big for WMP. That's Step 3's territory.
Step 3: Trim Your Media Files (15+ minutes)
If you're still getting the error, your library is genuinely too large. WMP has a hard limit — I've seen it around 65,000 tracks in practice, though Microsoft never officially publishes a number. You need to reduce the count. This isn't a bug; it's a resource constraint.
Option A: Remove Duplicate or Low-Quality Files
Use a tool like MusicBee or MediaMonkey (both free) to scan your folders for duplicates. These apps can find exact matches by audio fingerprinting. Delete any duplicates, corrupted files (0 byte files, partial downloads), and anything under 128 kbps that you don't actually listen to. That'll usually drop the count by 10-20%.
Option B: Move Files to External Storage
Don't want to delete anything? Move your least-played tracks to an external drive or a NAS. WMP can still index those if you want (via Organize > Manage Libraries > Music > Add), but keeping the local folder lean stops the error.
Option C: Switch to a Different Media Player
This is the nuclear option, but sometimes it's the right call. If you consistently have over 50,000 tracks, WMP isn't built for that. Use VLC (handles everything, no library limit), Foobar2000 (lightweight, customizable), or MusicBee (modern, handles huge libraries well). You won't see this error again.
My take: I've fixed this on more than 200 machines over the years. Step 1 resolves it for most people. If you're a power user with a massive collection, skip straight to Step 3 Option C — save yourself the headache. WMP is great for casual use, but it's not designed for a 100,000-track library.
That's it. No magic bullet, just straightforward fixes. Try them in order, and you'll be back to listening in no time.