Internal microphone not detecting input on macOS Sequoia

Hello! I’m facing a system-level microphone issue on macOS Sequoia. My Mac detects the built-in microphone (Internal Microphone is visible in Sound → Input), but the input level bar does not react to any sound at all. The same happens in all apps (Discord, FaceTime, etc.). The microphone itself is functional, but the system receives no audio input.

I have already reset all permissions using tccutil reset Microphone, tccutil reset Camera, and tccutil reset All. Apps request microphone access again and I grant permission, but there is still no input signal. I restarted the audio service using sudo killall coreaudiod. I checked Audio HAL plugins in /Library/Audio/Plug-Ins/HAL and ~/Library/Audio/Plug-Ins/HAL and these folders do not exist. I verified audio input routing in Control Center and Internal Microphone is selected. I also tried deleting the TCC.db file in Recovery Mode using /Volumes/Macintosh HD/Library/Application Support/com.apple.TCC/TCC.db, but even in Recovery I get “Operation not permitted.” The issue still persists.

I previously had the exact same issue on macOS Tahoe. I assumed it was an early OS problem and downgraded to Sequoia, but the issue has appeared again. So this problem occurs across two macOS versions, which makes me think it may be a system bug.

Mac model: MacBook Air 15” M3 (2024)

macOS version: Sequoia 15.7.2 (24G325)

If you need any additional diagnostic information (logs, audio device list, TCC data, etc.), please tell me and I will provide it.