When Windows can't hear your microphone — permissions, default device, exclusive mode and driver, in order

Microphone problems split into «no device at all», «device shows but no sound», «sound comes in but is quiet or noisy» and «only one app fails». Work through the Windows side in the order below and, after each step, check with the «Mic Test» web tool whether the level meter moves. That narrows down where it is stuck.

Sort it by symptom first

1. Privacy settings — may apps use the mic?

• Under Settings → Privacy & security → Microphone, check that «Microphone access», «Let apps access your microphone» and «Let desktop apps access your microphone» are on.
• As Microsoft's article notes, desktop apps do not appear in the app list and cannot be blocked one by one. Browsers such as Chrome and Edge are desktop apps, so with the last switch off the web mic test cannot open the mic either.
• Browsers also keep a permission per site. If the site information left of the address bar shows the microphone as «Blocked», set it to «Allow» and reload.
• If you use a webcam's built-in mic, the «Camera» permission in the same place must be on too.

2. Default input device — is that mic selected?

• Under Settings → System → Sound → Input, pick the mic in «Choose a device for speaking or recording», make sure its «Input volume» is not 0, and see whether the bar moves in «Microphone test».
• With a laptop mic, a webcam mic and a headset all present, an app often grabs a different one. Video-call programs usually choose the mic in their own settings, separately from the Windows default.
• Check the headset's mute button, and whether the mic boom mutes when raised.
• In the web mic test, switch «Input device» one by one to compare on one screen which mic actually picks up sound.

3. Exclusive mode — is another program holding the mic?

Windows audio has a «shared mode», where several apps use a device together, and an «exclusive mode», where one app has the device to itself. According to Microsoft's documentation, an attempt to open a device in shared mode fails while the device is already operating in exclusive mode. Recording, streaming and voice programs sometimes use exclusive mode, and while one runs in the background other apps see the device as «in use».

• Symptom: one program works, but the browser or another app cannot open the mic. The web mic test says «The microphone could not be opened» and points to another program holding it or a driver problem.
• First close all recording, call and streaming programs (including ones in the notification area) and try again.
• Where the setting lives: Run (Win+R) mmsys.cpl → «Recording» tab → the mic → Properties → «Advanced» tab, two check boxes: «Allow applications to take exclusive control of this device» and «Give exclusive mode applications priority».
• Microsoft's documentation says exclusive mode is allowed by default. With the first box cleared the device can only be used in shared mode, so a program that really needs exclusive mode may fail instead. Use it as a temporary switch to compare.

4. Driver — no device, or broken after an update

• In Device Manager (right-click Start), look for a warning icon under «Audio inputs and outputs» and «Sound, video and game controllers».
• Microsoft's order: «Uninstall device» on the audio device (tick «Attempt to remove the driver for this device») → restart the PC → if it does not come back, «Scan for hardware changes» → update the driver.
• If it stopped working after a Windows update, look at «Roll Back Driver» on the device's Driver tab. On a laptop, try the audio driver from the PC maker first.
• Microsoft's article notes that audio enhancements can cause problems. Turn them off for that device in Sound settings and compare.
• Plug a USB mic or headset into another USB port (directly into the PC, not a hub) to compare.

5. Quiet or noisy — read the numbers

The web mic test shows the current level and peak in dBFS, the «noise floor» while you are silent, and how often the signal clips. 0 dBFS is the digital maximum; touching it cuts the sound off.

• If clipping keeps rising, lower the Windows input volume (or the mic's own gain).
• A high noise floor while nobody speaks is worth comparing against mic placement (distance from fans and chargers), power or ground noise, and another mic socket. Values vary by device and driver, so there is no fixed baseline.
• Toggle echo cancellation, noise suppression and auto gain and compare «Record 5 s and play» to hear the difference between what a video-call app sends (processing on) and the raw mic (processing off).

If it is a Bluetooth headset mic

The moment the mic of Bluetooth earbuds or a headset is used, the headset switches to «hands-free» mode and sound drops to call quality. If the mic works but everything sounds muffled, that switch rather than a fault may be the reason — see the hands-free section of the Bluetooth headphones guide. Whether Bluetooth audio is in hands-free or stereo mode right now is shown by the «Wireless» tab of PortDock Port Inspector or the Bluetooth audio mode in Hardware Tester (both free Windows programs).

Narrow it down with the web tool

The web mic test opens the mic through Windows like any other app. If the level moves there, the device, driver and Windows permissions are working, and what remains is the mic choice and permission of the app that fails. If it does not move there either, go back to steps 1–4. Sound is handled only inside the browser and is never sent anywhere.

Sources

• Microsoft Support — Fix microphone problems — the three mic permission switches, default input, uninstall and rescan
• Microsoft Support — Fix sound or audio problems in Windows — turning off audio enhancements, driver rollback
• Microsoft Learn — Exclusive-Mode Streams — exclusive mode allowed by default, the two per-device check boxes
• Microsoft Learn — IAudioClient::Initialize — shared-mode open fails while the device is in exclusive use (AUDCLNT_E_DEVICE_IN_USE)

Published 2026-10-30