Fix NS_E_DUPLICATE_DRMPROFILE (0XC00D1B90)

You're trying to play a DRM-protected file — usually a WMA or WMV from an old purchase — and Windows Media Player stops dead with NS_E_DUPLICATE_DRMPROFILE (0XC00D1B90). The error text says "The profile ID is already used by a DRM profile", but that's not a clue, it's the whole story. This happens after you've reinstalled Windows, restored a backup, or migrated from an older PC and your old DRM licenses are half-dead in the Windows Media DRM (WMDRM) registry hive.

What's actually happening here is that Windows stores DRM profiles under HKLM\SOFTWARE\Microsoft\WindowsMedia\DRM. Each profile gets a unique ID, and when a previous copy of the OS orphaned these entries, you end up with two profiles pointing to the same ID. Windows doesn't know which to read, so it throws the duplicate error instead of just picking one. Clean machines never see this. You only hit it after a botched migration or a restore that kept old registry keys but lost the matching license files.

The fix is to clear out the stale DRM profile entries and let Windows rebuild them fresh. Don't worry — this doesn't nuke your media files. It just resets the license cache, and you'll re-acquire licenses the next time you play the content (assuming the store is still alive). Here's how to do it properly.

Fix: Reset the DRM Profile Registry Keys

Close Windows Media Player and any app that uses DRM (like Movies & TV or an old Zune client). If you don't, the registry entries are locked and the fix won't stick.
Open Regedit as administrator. Win+R, type regedit, press Ctrl+Shift+Enter.
Back up the DRM key first. Right-click on HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsMedia and choose Export. Save the .reg file somewhere — you'll want it if something goes sideways.
Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsMedia\DRM. You'll see subkeys like Profile and DRMProfiles (sometimes Profiles). The exact name varies between Windows 7 and Windows 10/11.
Delete the entire DRM folder, not just the entries inside. Right-click on DRM and select Delete. Yes, the whole thing. Windows will recreate it from scratch on the next DRM operation.
Also clear the per-user copy. Go to HKEY_CURRENT_USER\Software\Microsoft\MediaPlayer and delete the DRM subkey there if it exists. This one stores your personal license state and often has the same collision.
Reboot. Not strictly required, but it guarantees the old handles are gone from memory.
Try playing the file again. Windows will rebuild a clean DRM profile. If the file's license server is still online, you'll get a prompt to acquire a new license. If it's dead (old Zune, some DRM stores shut down years ago), you're out of luck — that's not a fixable error, it's a dead store.

The reason step 5 works is that deleting the whole folder removes both the bogus profile IDs and the orphaned references. If you only delete individual values, Windows might re-import the same stale data from the backup you made or from a hidden cache. Nuking the folder forces a clean build.

What to check if it still fails

If the error persists after the reset, two things are usually wrong:

You missed the per-user key. Even after clearing HKLM, the HKCU entry can re-inject the duplicate. Go back and double-check both locations. On Windows 10 1809+ the per-user path is HKCU\Software\Microsoft\MediaPlayer, but on older builds it might be under HKCU\Software\Microsoft\WindowsMedia. Search for DRM under HKCU\Software\Microsoft to find it.
The licenses are corrupt, not just the profiles. Run drmclean.exe from the Windows Media SDK if you have it — it's a Microsoft tool that wipes all WMDRM settings. But honestly, I've found that a full registry reset works just as well, and you don't need to hunt for a legacy SDK. Another option: use del /s /q %WINDIR%\ServiceProfiles\LocalService\AppData\Local\DRM in an admin command prompt to clear the file-based license cache. That's where the actual license blobs live.

One more thing — if you're on a corporate machine, Group Policy might be re-importing DRM settings at every logon. Check HKLM\SOFTWARE\Policies\Microsoft\WindowsMediaPlayer for any DRM-related policies. A sysadmin can disable them, but you probably shouldn't if it's a managed device.

This error is rare enough that you won't find it in most forums, but the fix is straightforward once you know the registry layout. The hardest part is accepting that old DRM content might be permanently unplayable if the license server is gone. That's not a technical failure — it's the DRM model doing its thing when the store shuts down.