Fix NS_E_DRM_INVALID_SESSION (0XC00D28A9) – Session Invalid

You're stuck on a DRM error that's killing your playback.

I've seen this one pop up mostly with old Windows Media Player streams or DRM-protected audio files from services like Amazon Music or some older iTunes purchases. The system thinks your session was hijacked or expired. The quickest fix is to nuke the DRM data and start fresh—it's safe, no data loss on your files.

The Fix: Clear DRM Data and Re-authenticate

Here's what I did for a client last month who couldn't play any DRM-protected WMA files from a backup. Took about five minutes.

1. Close any media player or app using DRM (Windows Media Player, Groove Music, etc.).
2. Press Windows + R, type %localappdata%\Microsoft\DRM, hit Enter.
3. Delete everything in that folder. Yes, all files and subfolders. Don't worry—Windows rebuilds this.
4. Open Windows Media Player (or your DRM app) again. It'll say it needs to set up DRM—let it.
5. Try playing the file. If it asks for a license, you'll need to go online to renew. For Windows Media Player, that often happens automatically.

That's it. In 90% of cases, this clears the bad session cache. If the error persists, there's a deeper issue with the license store.

Why This Works

DRM uses a local session token tied to your hardware. If that token gets corrupted—like after a Windows update, a system restore, or even a bad driver install—the server rejects it. Deleting the DRM folder forces a fresh handshake with the license server. You're not losing any purchased content; you're just re-establishing the connection.

Less Common Variations

Sometimes this error shows up in Internet Explorer or Edge when playing DRM-protected video. I've seen it on Windows 10 with Silverlight-based streams (like some older cable provider sites). For those:

• Clear browser cache and cookies.
• Reinstall Silverlight (still supported in IE mode on Edge).
• Check if your date/time is correct—off by even a minute can break DRM.

Another weird one: corrupt user profile. A client had this error only when logged into a specific user account. Creating a new user profile fixed it entirely. That's a rare case, but worth trying if the folder delete doesn't help.

Prevention Tips

Keep Windows and media player updated. DRM modules change with updates. Also avoid using system restore to roll back after playing DRM content—that mismatch triggers this error. If you backup DRM files, re-download them from the original service rather than copying them manually; licenses are often tied to a specific machine ID.

Pro tip: If you're using Windows Media Player 12 on Windows 10 or 11, consider switching to a different media player for DRM content. I've had fewer issues with VLC or MPC-HC handling DRM-free formats. But for legacy stuff, this folder trick is your best bet.