01 — Establish the symptom
Does the meter move at all?
Look at the Mic/Aux row in the Audio Mixer and speak. Either the meter moves or it does not, and that single observation splits the problem in half.
If it moves, OBS is hearing you and the problem is what happens after: the source is muted, monitoring is set to Monitor Only, or it is not assigned to the recording track. Those are covered in our guide to OBS not recording audio.
If it does not move at all, the signal is not reaching OBS, and the rest of this page applies.
Check the mute button first. A muted source shows a crossed-out speaker, and it is the easiest thing in the interface to click by accident.
02 — Check first
Operating system permission
On macOS, open System Settings, Privacy and Security, Microphone, and confirm OBS is listed and switched on. If OBS is not listed at all, the permission was never requested, which happens with certain installation methods.
On Windows, Settings, Privacy and Security, Microphone, and check both the general microphone access and the separate toggle for desktop apps. The second one is the one people miss.
Quit and reopen OBS after changing anything here. It reads permissions at launch, so a change made while it is running looks like it did nothing.
System updates can revoke this, so it is worth checking even when OBS was working last week.
Toggling the permission off and on, then restarting OBS, fixes cases where the setting already looks correct.
03 — Check second
Which device is selected
Settings, Audio, and look at Mic/Auxiliary Audio under Global Audio Devices. Set it explicitly to your microphone rather than leaving it on Default.
Default follows whatever the operating system considers the current input, which changes when you plug in headphones, join a call, or connect a monitor with a built-in microphone.
If you have an Audio Input Capture source in your scene as well as the global device, you may have two microphone sources and be watching the wrong meter. Remove the duplicate.
If your microphone is not in the list at all, OBS cannot see the device. Check it appears in your system sound settings first, and use Rescan or restart OBS if you connected it after launching.
04 — Check third
Another application has it
Video conferencing apps hold the microphone after a call ends, and some audio software takes exclusive control. OBS then sees the device and gets nothing from it.
Quit everything that touches audio, including things sitting in the menu bar or system tray, and restart OBS.
On Windows, there is also a per-device setting: in Sound Control Panel, under the device's Advanced tab, uncheck Allow applications to take exclusive control. That stops one program locking out everything else.
05 — Check last
Filters muting your own signal
Right-click the microphone source and choose Filters. If there is a Noise Gate with a threshold set too high, it closes on everything you say and the meter barely moves.
Noise Suppression set aggressively can do something similar on a quiet microphone, treating your voice as background.
Remove every filter temporarily and test. If the microphone comes back, add them one at a time to find which one was responsible, and set its threshold while watching the meter.
Also check the input gain on the source, and the hardware gain knob if you are using an interface. A very quiet signal can look like no signal on a small meter.
Record in a browser instead
No device selection, no filters, no permissions to chase.
Record without configuring a single device.
Try Hilite free.