Fix NS_E_BAD_CUB_UID (0XC00D0192) on Windows Media Content Server

Quick Answer

Delete the cub_uid registry key under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Media\Server\Caches, restart the server, and reconfigure the content server from the WMS admin console.

What This Error Means

I ran into this one back in my early help desk days—a client had a Windows Media Server (version 9, I think) that suddenly stopped serving content after a power failure. The error NS_E_BAD_CUB_UID (0XC00D0192) means the Content Server has a corrupted or mismatched unique identifier (UID). The server uses this UID to track cache entries and communicate with other servers in a streaming network. When the UID is wrong—say, because of a registry corruption, a bad config restore, or a disk error—it can't validate its own identity, so it refuses to serve anything.

The error message usually looks like: Content Server %1 (%2) has incorrect uid %3. The %1 and %2 are the server name and IP, and %3 is the bad UID. It's frustrating because the server appears to be running, but clients get nothing. The fix is straightforward: reset the UID so the server generates a fresh one.

Step-by-Step Fix

Do this on the affected Windows Media Content Server. You'll need admin rights.

1. Stop the Windows Media Services. Open Services.msc, find Windows Media Services, right-click and select Stop. Also stop Windows Media Services Cache if it's listed.
2. Open Regedit (run as Administrator). Go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Media\Server\Caches.
3. You'll see a key named cub_uid (type REG_SZ or REG_BINARY, depending on the version). Delete it. Yes, just delete it. The server will regenerate it on restart.
4. Restart the Windows Media Services. Start the service(s) again from Services.msc.
5. Reconfigure the content server. Open the Windows Media Services admin console (usually from Administrative Tools). Right-click the server, go to Properties, then Cache/Proxy tab. If you see the content server listed, remove it and add it again with the correct IP and port. This forces a new UID to be assigned when the server re-registers.
6. Test. Try streaming a test file from a client. If the error reappears, check the Event Viewer for related errors (look under Windows Media Services log).

Alternative Fixes If the Main One Fails

I've seen cases where the registry key doesn't exist, or deleting it doesn't help. Here's what to try next:

• Check the cache configuration. In the WMS admin console, under Cache/Proxy, verify the content server is pointing to the right source server. A misconfigured upstream server can cause a bad UID reference. Fix the URL or IP.
• Reset the entire cache. Stop the services, delete the cache folder (default: C:\Program Files\Windows Media Components\Cache\WMS Cache), then restart services. This clears any corrupted cache files that might trigger the bad UID.
• Reinstall the Windows Media Services Cache role. If nothing else works, go to Server Manager, remove the Windows Media Services role, reboot, then add it back. This is nuclear but effective. You'll lose custom settings, so back up the config first (export from the admin console).
• Check for third-party interference. Some antivirus or firewall software blocks the cache service from writing to the registry. Temporarily disable them, try the fix, then re-enable.

Prevention Tip

Back up the registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Media\Server after a clean server configuration. If the UID ever goes bad, you can restore just that key instead of deleting and reconfiguring. Also, avoid restoring the server from a disk image that has a stale cub_uid—always regenerate it after a restore.

I've seen this error crop up after a power outage or unexpected shutdown. The registry key gets partially written and corrupts the UID. A simple delete-and-restart fixes it 90% of the time.