NS_E_DRM_LICENSE_CERT_EXPIRED Fix: 0XC00D27DF on Windows

Fix 1: Sync your system clock (the #1 cause)

What's actually happening here is a time mismatch. The DRM license server signs certificates with a validity window, and your PC's clock is way outside that window. When the difference is more than a few minutes, Windows Media Player refuses to trust the license cert. This is the most common cause by far, and it's also the easiest to fix.

A real-world trigger: you dual-boot Windows and Linux, or your CMOS battery is dying. Every time you boot into Linux, it sets the hardware clock to UTC, then Windows reads it as local time — suddenly you're 5 hours off. Or you disabled automatic time sync to fix a game's anticheat, then forgot about it.

Here's the fix:

1. Right-click the clock in the taskbar, select Adjust date/time.
2. Turn on Set time automatically and Set time zone automatically (if available).
3. Click Sync now under Additional settings. If it fails, run this from an elevated command prompt:

w32tm /resync

If that throws an error, force it with:

net stop w32time && w32tm /unregister && w32tm /register && net start w32time

After resyncing, try playing the file again. If you're on a corporate network with a domain controller, your clock might be forced to sync with the DC — in that case, contact your IT admin, because local changes will be overwritten.

The reason this works: DRM licenses are time-based. The certificate has a notBefore and notAfter date, and if your system time falls outside that window, the cert is considered expired — even if the license itself is still valid. Put your clock back in the right range and the validation passes.

Fix 2: Reset the DRM folder

If your clock is fine and you're still getting the error, the DRM store on your machine is likely corrupted. This happens when a previous playback session crashed, or when a system restore rolled back files mid-write. The DRM folder is hidden and protected, but you can safely delete it — Windows will recreate it on next playback and re-download the necessary licenses.

Here's the risk: you'll lose any licenses for content you purchased or rented. If you're watching a rented movie and the license is stored locally, deleting the folder means you'll need to re-download the license. If you own the content (like a purchased WMV), the license server will re-issue it automatically the next time you try to play. Just don't delete this folder if you're offline and need to watch something you've already licensed.

Steps:

1. Close Windows Media Player completely. Check the tray — it might still be running.
2. Open File Explorer, paste this into the address bar:

%USERPROFILE%\AppData\Local\Microsoft\Media Player

Actually, the DRM folder is one level up. The correct path is:

%USERPROFILE%\AppData\Local\Microsoft\DRM

3. Select everything inside (Ctrl+A) and delete. Windows will ask for admin permission — allow it.
4. Restart WMP and try playing the file again. It'll rebuild the DRM store automatically.

If you get a "file in use" error, open Task Manager, end WMP.exe and drmstore.exe if present, then retry.

What's actually happening here: the DRM store is a small database of licenses plus a machine-specific key. When it gets corrupted, the license validation fails before it even checks the certificate dates. Deleting it forces a clean slate. The reason this is only a fix for local corruption, not a universal one, is that some DRM errors come from the server side — but this specific code (0XC00D27DF) points to certificate expiry, which can be either a client-side clock issue or a broken local cache.

Fix 3: Reinstall Windows Media Player or use a different player

Sometimes the DRM components themselves are broken. On Windows 10 and 11, WMP is an optional feature. You can disable and re-enable it to force a fresh install of the DRM DLLs.

Here's the catch: this doesn't always work because the DRM system is tied to the OS and can't be fully replaced by toggling a feature. But it's worth a shot if the first two fixes didn't do anything.

Steps:

1. Open Control Panel → Programs → Turn Windows features on or off.
2. Scroll down, uncheck Media Features → Windows Media Player.
3. Reboot, then go back and re-check it. Reboot again.

If you're on Windows 7 or 8, uninstall WMP from the same dialog, reboot, reinstall.

The real fix, though, might be to just stop using WMP. For protected content (WMV, ASF, some purchased music), the DRM server might have shut down — Microsoft ended the DRM service for older content in 2019. If that's the case, no local fix will help. The certificate is expired because the server that issued it no longer exists. In that situation, your only option is to rip the file (if legal) or use a player that doesn't enforce DRM — though that's a gray area.

For unprotected content, VLC Media Player is a solid replacement. It ignores DRM entirely and handles most codecs. But if you need DRM playback (e.g., for a corporate training video), you'll need to check with the content provider for a new license.

Quick-reference summary

Go start with the clock. Nine times out of ten that's it. If not, nuke the DRM folder. Don't bother with registry hacks or third-party DRM cleaners — they're snake oil and can make things worse.