If the mic test says the microphone is blocked, work through Windows privacy, browser permission, app conflicts, and the selected input device in that order.
Nothing you say or show leaves this device.0 network requests carrying media ยท 0 bytes uploaded
See the proof
Watch the live counter. It stays at zero for media uploads while you run a mic, camera, or speaker check.
Verify it yourself. Open DevTools, choose Network, run a test, and look for uploads. In Chrome or Edge press Ctrl+Shift+I. In Firefox press Ctrl+Shift+E.
CSP guardrail. Content-Security-Policy is a browser rule that limits where this page can send data; media is not allowed to leave this page.
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Start with the Windows switch
Open Windows Settings, choose Privacy & security, then Microphone. Turn on microphone access for the device and make sure desktop apps are allowed to use the microphone. Browser-based tests are usually counted as desktop app access, so this switch can block Chrome, Edge, and Firefox even when the browser looks correctly configured.
After changing the setting, return to MicAndCam and use the Start mic button again. The browser may show a fresh permission prompt or reuse the site setting that is already stored for micandcam.com.
Settings > Privacy & security > Microphone > Let desktop apps access your microphone: On.
Check that the correct input is selected in Windows Settings > System > Sound > Input.
Then check the browser permission
Browsers keep a separate permission for each website. In Chrome or Edge, use the icon beside the address bar, open site permissions, and set Microphone to Allow or Ask. In Firefox, use the permission icon in the address bar, remove the blocked microphone permission, then try again and choose Allow.
If the browser says permission is already allowed but MicAndCam still cannot start, the microphone may be busy in another app, unplugged, muted, or blocked by Windows privacy settings.
If the meter is still silent
A permission fix only lets the browser open the device. It does not guarantee the microphone is the right one or loud enough. Speak at a normal distance, check any hardware mute switch, raise the Windows input level, and choose another input in the MicAndCam picker if one is available.
Meeting apps can also hold or change devices. Close Zoom, Teams, Discord, browser call tabs, screen recorders, and audio tools, then reload the mic test.
Windows has a device-level privacy switch and an app-level desktop access switch. If either one blocks the browser, the site cannot receive microphone audio even when the website permission looks allowed.
Why does Firefox say permission is granted but the mic still fails?
Permission is only one part of the chain. Another app may be using the device, the wrong input may be selected, the headset may be muted, or Windows privacy settings may still block desktop apps.
Is an online mic or webcam test safe and private?
It can be when the tool runs locally. MicAndCam analyzes microphone levels, camera preview, snapshots, and recordings in your browser and does not upload media. You can verify this with the live counter or your browser's Network panel.