Fix guide · Microphone test
How to fix "NotFoundError: Requested device not found"
NotFoundError means the browser looked for a microphone or camera and found none that matches. It shows up as "Requested device not found", "Device not found" or "No video track available". The cause is nearly always simple: nothing is plugged in, the device is switched off in the system, or the browser is pointed at a device that is no longer there.
Quick fix checklist
- 1Check that the microphone or camera is plugged in firmly, or paired and connected if it is wireless.
- 2Try a different USB port and avoid unpowered hubs and adapters.
- 3Make sure the device is enabled: on Windows check Settings > System > Sound > Input, and Device Manager for cameras.
- 4Look for a physical mute switch, a camera privacy shutter or a function key that turns the device off.
- 5Pick another device from the list in the test, or unplug and replug, then press Check again.
Why the browser finds no device
A desktop PC without a webcam or a built-in microphone really has nothing to find. On laptops the device may be disabled in the BIOS, turned off with a shortcut key or hidden by a driver problem. Bluetooth headsets only expose a microphone while they are connected, and some only after you choose them as the system input.
Pages that remember a specific device can fail too. If you unplug a USB microphone and the page still asks for it by its stored ID, the browser reports NotFoundError until you choose another input.
When it only fails in one app
If the microphone test or webcam test finds your device but another site does not, reset that site permission and select the device again. If neither finds it, the problem is the system or the hardware, not the website.
FAQ
Common questions
What does "No video track available" mean?
The camera stream started with no video, usually because no camera is connected, it is disabled, or another program is blocking it.
How is NotFoundError different from NotAllowedError?
NotAllowedError means permission was refused. NotFoundError means there is no matching device at all, even though permission may be fine.
Can a driver update fix it?
Sometimes. If Device Manager lists the camera with a warning icon, reinstall or update its driver, or unplug it and let the system detect it again.
Does a Bluetooth headset count as a microphone?
Yes, once it is connected and selected as the input. Some headsets switch to a lower quality call mode when the microphone is used.