NS_E_DRM_CERTIFICATE_SECURITY_LEVEL_INADEQUATE Fix

What causes this error

You're seeing 0xC00D28AE (NS_E_DRM_CERTIFICATE_SECURITY_LEVEL_INADEQUATE) when trying to play protected content — usually WMV, ASF, or Silverlight streams. The DRM certificate on your machine is either corrupted, expired, or wasn't issued with a high enough security level for the action the player requested.

This hits most often on Windows 10 after a system update or after installing a newer version of Windows Media Player. Silverlight apps (like old Netflix or BBC iPlayer) trigger it too. The error is the system saying: I don't trust this certificate enough to let you play that.

Cause 1: Corrupted DRM data — the reset fix

Nine times out of ten, the DRM store got corrupted. An update or a crash halfway through a DRM renewal request breaks the certificate hierarchy. The fix: nuke the store and let Windows rebuild it.

1. Close Windows Media Player and any browser that could be using Silverlight.
2. Open File Explorer and paste this into the address bar: %PROGRAMDATA%\Microsoft\Windows\DRM
3. Delete everything in that folder. You'll need admin rights. If it says files are in use, you missed something — check Task Manager for WMP or Silverlight processes.
4. Open an admin Command Prompt and run: regsvr32.exe %windir%\system32\drmv2clt.dll. If that fails, also run regsvr32.exe %windir%\system32\dxmasf.dll (on older Windows versions).
5. Reboot. Then play the content again. Windows will re-download fresh DRM certificates on the first attempt.

The reason step 3 works: The DRM certificate store is just a folder of license files and cert blobs. When it's gone, Windows Media Player treats it as a clean slate and requests new certs from the license server. Those new certs come with the correct security level for the current OS and player version.

Cause 2: Missing or outdated Silverlight

If the error happens in a browser for a Silverlight-based stream (e.g., older Netflix or Amazon Video), the problem might be Silverlight's DRM component, not Windows Media Player's.

1. Go to Control Panel > Programs and Features. Find Microsoft Silverlight.
2. Click Uninstall, and let it finish. Reboot.
3. Download the latest Silverlight installer from Microsoft's official site (yes, it's still hosted, even though Silverlight EOL'd). Get version 5.1.50918.0 or later.
4. Install, reboot again, and try the stream.

What's actually happening here is Silverlight's DRM subsystem (Media Foundation's Protected Media Path) relies on a separate set of certificates. If they're missing or lower than the content's requirement, you get the same errorcode. Reinstalling pulls down fresh certs that match the current security demands.

Cause 3: Windows version with restricted DRM

Some Windows versions — especially N editions (I'm looking at you, Windows 10 N) — don't include Windows Media Player or its DRM components by default. You can install the Media Feature Pack, but even then, the DRM certificate chain might not have the required security level for high-value content (like 1080p protected streams).

1. Check your Windows edition: Settings > System > About. If it says 'N', you're on a restricted edition.
2. Download and install the Media Feature Pack for your exact Windows version from Microsoft's site.
3. After install, run Windows Update and grab all pending patches.
4. Reboot. Then do the reset method from Cause 1 as a follow-up.

The reason step 2 works: The Media Feature Pack includes DRM client libraries that N editions omit. Without them, Windows can't negotiate a secure enough channel with the license server, and the cert request fails with an inadequate security level. Adding the pack gives the OS the ability to request a higher-level cert.

Quick-reference summary

Start with cause 1 — it hits 90% of cases. If you're on an N edition, skip straight to cause 3 and do the reset afterward. And if you're still stuck, check event logs under Applications and Services Logs > Microsoft > Windows > Media Center for more specific DRM error codes.