When Discord stops picking up your microphone, the cause is nearly always one of four things: something is muted, the wrong device is selected, the operating system is blocking access, or a setting inside Discord is filtering you out. Work through them in that order, cheapest check first, and you will usually be talking again within a few minutes. The mistake is panicking and reinstalling everything while your friends wait in the lobby.
Begin with the embarrassing checks
Nobody wants the fix to be a mute switch, and it very often is. Many headsets have an inline mute slider or a flip-to-mute boom, and some USB mics have a touch-sensitive mute on top that a stray hand can trigger. Check the hardware first.
Then check Discord’s own mute and deafen icons near your username, and remember that a server moderator can server-mute you, which shows a different icon and cannot be undone from your side. Finally, look at whether the green ring lights up around your avatar when you speak. If it lights but nobody hears you, the problem is on their end or with the channel. If it never lights, Discord is not receiving audio, and you continue down the list.
Is Discord listening to the right device?
Open the voice settings and look at the input device. If it says default, Discord is trusting the operating system’s choice, and that choice changes more often than people expect. Plugging in a webcam, a capture card, a game controller with a headphone socket, or a virtual audio tool can each register a new input and sometimes steal the default slot.
Select your microphone explicitly by name, then run the mic test in the same settings page. If you hear yourself played back, the hardware path works and the remaining suspects are all inside Discord. If the meter stays flat, the problem is further upstream.
Is the operating system letting Discord in?
Both Windows and macOS have privacy controls that decide which applications may use the microphone, and both can block Discord without showing any obvious error. Discord simply receives silence.
Windows
Look in the privacy section of system settings for microphone access. There is a general switch for microphone access, and a separate one allowing desktop apps to use it. Both need to be on. While you are in the sound settings, confirm that the mic appears as an input device, is not disabled, and that its meter moves when you talk. If Windows itself cannot see movement, no Discord setting will help, so try another USB port or cable and check that the mic works in another program.
macOS
On a Mac, microphone permission is granted per application in the privacy and security settings. If Discord is missing from the list or unticked, enable it and restart the app. Permissions can also need re-granting after a major system update, which explains the mic that worked fine last week.
Settings inside Discord that silence you
Once the system can hear the mic and the correct device is selected, a handful of Discord options are the usual culprits. Input sensitivity is the big one: if the manual threshold is set too high, Discord decides your voice is background noise and never transmits. Switch to automatic sensitivity temporarily, or drag the threshold down, and watch whether the indicator responds.
Push to talk catches people out as well. If the mode was switched on by accident, or the keybind was cleared, you can talk all evening without sending a word. Input volume dragged to the bottom has the same effect. There is also a reset voice settings button at the bottom of the page, which is a reasonable step if you have been tweaking for a while and lost track. For the less common causes, such as exclusive-mode conflicts and audio subsystem options, the page on Discord mic not working goes into more detail than there is room for here.
One more quirk on Windows: if Discord runs with normal privileges while your game runs as administrator, push-to-talk keypresses may not register while the game window is focused. Running Discord as administrator too resolves it.
When nothing on the list has worked
Now the heavier steps make sense. Restart Discord fully, quitting it from the system tray so it is not just minimized. Restart the computer, which clears stuck audio drivers more often than it should. Try the browser version of Discord: if the mic works there, the desktop install is the problem and a clean reinstall is justified. If it fails there as well, test the microphone on another device to rule out dead hardware.
The order is the whole trick
Mute switches, device selection, system permissions, Discord settings, then restarts and reinstalls. Each step takes under a minute and rules out a whole category of causes. Go down the list calmly, change one thing at a time, and test after each change so you know which fix was the real one.