How to Fix an Empty OBS Audio Mixer or a Missing Microphone

Identify the symptom and environment

An empty audio mixer usually means OBS does not have any active audio devices assigned to a scene or to the application as a whole. This can appear as a blank mixer panel, no input level movement, or a microphone missing from the device list. Note when the problem happens: at startup, after disconnecting a USB microphone, after an operating system update, or only in a specific scene collection. The relevant details are the operating system, the OBS version you are using, the microphone or capture source model, and whether the problem affects only that source or every audio input.

Isolate where the fault occurs

Separate the possible causes before changing many settings. First confirm whether the microphone works outside OBS. Open the operating system's sound settings and speak into the microphone. If there is no input level movement there, the problem is likely with the device, cable, port, or system-level privacy permission rather than OBS.

Check whether the device is visible to the system. A USB microphone connected through a docking station or hub may show up only when plugged directly into a known working port. A device that appears in system settings but not in OBS may be held by another capture application, or the application may lack permission to access the microphone.

On Windows, open the privacy and security settings for the microphone and verify that desktop applications are allowed to use it. On macOS, check the privacy settings for the microphone in System Settings or System Preferences. OBS may need to be restarted after permission is granted. If OBS does not appear in the permission list, add it explicitly.

If only one capture source disappears, try another input device or recording application. That can distinguish a damaged or occupied source from a problem in OBS itself.

Try reversible fixes in order

Start with the least disruptive change. In OBS, open the audio settings and look at the global audio devices section. If a microphone is selected there, remove or change the selection and then set it again to the correct device. The labels in the menu are generated from the operating system.

Close other applications that may claim the microphone. Video call software, voice chat tools, browsers, and screen recorders can prevent OBS from opening the same input. Closing them and restarting OBS is often enough.

When the device is present but shows no input level, open the source properties and confirm that the intended device is selected. Also check the level controls in OBS and in the system sound settings. A muted or very low system input level can look like a missing source.

If OBS was already running when the microphone was connected, close OBS fully and reopen it. A device that was unplugged and reconnected may not be picked up until the next launch.

For sample rate problems, compare the system audio settings with OBS. Different sample rates between the device and the application can prevent usable audio even when the device appears. Changing the system device to match the OBS sample rate setting is a reversible check.

Confirm the result

Speak into the microphone while watching the mixer in OBS. The input level for that source should move when the device is working. Also check that the audio meter is not just hidden or collapsed. If the problem was affecting a recording or stream, make a short local test recording to confirm that the sound is captured.

Do not use factory resets or broad security changes as a first confirmation step. A successful test is a source appearing in the mixer and responding at a normal input level.

If the problem remains

Record which observations were made so the next attempt is informed: whether the device appears in the system, whether it produces level movement in the system or another app, what is selected in OBS audio settings, and when the mixer becomes empty. A microphone that works in other applications but not in OBS is a different problem from one that does not work anywhere.

If OBS cannot see the microphone in any scene collection and the issue began after an update, check whether your OBS version has a known change in audio device handling. An older or portable capture device may need the manufacturer's driver or control software for the operating system to expose it correctly. When a device does not appear in the system at all across multiple ports and computers, contact the device manufacturer or a repair service rather than assuming the hardware has failed.