You're staring at NS_E_SOURCE_NOTSPECIFIED and you're not alone—it's a classic Windows recording headache. The fix is quick, so let's get to it.
The Quick Fix
- Right-click the speaker icon in the system tray and select Sounds (or Open Sound settings).
- Go to the Recording tab.
- Find the microphone or line-in device you intend to use. If it's not listed, right-click an empty area and check Show Disabled Devices and Show Disconnected Devices.
- Right-click your preferred device and choose Set as Default Device. Also set it as Default Communication Device.
- Click OK and restart your recording app.
That's it for most cases. The error disappears because Windows now knows which input to hand to your software.
Why This Works
What's actually happening here is that your application (OBS, Audacity, Zoom, whatever) is asking Windows for a capture source—a microphone, webcam, or line input—and Windows is saying "I don't have one set up." The error code 0xC00D1B85 literally translates to "The source has not been set up completely."
Setting a device as default tells the system which endpoint to use when an app doesn't specify one. Most programs rely on the default device rather than letting you pick a specific one from a dropdown. If that default is empty or points to a disconnected device, you get this error.
The reason step 3 matters is that Windows hides disabled devices by default. If your mic was previously disconnected or disabled by a driver update, it won't appear in the list—so you can't select it.
Less Common Variations
Sometimes the default device is set, but the error still appears. Here are the other culprits I've seen:
1. App-Specific Permissions (Windows 10/11)
Windows 10 and 11 let you block microphone access per app. If your app is denied, it gets nothing—even if the default is fine.
- Go to Settings > Privacy & security > Microphone.
- Make sure Microphone access is on.
- Scroll to Let apps access your microphone and toggle it on.
- Check that your specific app is allowed.
This is the #1 hidden cause after the default device fix. I've lost count of how many times this solved it for clients.
2. Disabled Audio Service
If the Windows Audio service is stopped, recording dies too. Open Services.msc, find Windows Audio, and set its startup type to Automatic and start it if it's not running.
3. Driver Issues After an Update
Windows updates sometimes nuke your audio driver. If the device shows as Not plugged in or has a yellow exclamation in Device Manager, reinstall the driver.
- Press Win + X and select Device Manager.
- Expand Audio inputs and outputs.
- Right-click your mic and choose Uninstall device.
- Then click Action > Scan for hardware changes—Windows reinstalls it.
4. Privacy Settings for Desktop Apps
Older desktop apps sometimes bypass the per-app list, but they still honor the master switch. If that master toggle is off, nothing works.
Prevention
You won't see this error again if you do one thing: always set a default recording device before launching a recording app. I'm not talking about every time—just after you plug in a new mic, update drivers, or install a major Windows feature update.
Also, when you run a fresh install of OBS or similar, take the 30 seconds to check its audio settings. Many apps will let you pick a device explicitly, which bypasses the default entirely. Do that and you're immune to this error.
And if you're a laptop user—plug in your external mic before the app starts. Windows gets fussy about hot-swapping capture devices mid-session. It's a quirk that's been around since Vista, and it's not going away.
That's the whole story. Set the default, check permissions, and you'll be recording without drama.