When your POCO F6's volume buttons stop responding, it's usually a software hiccup or some physical obstruction. The good news is you can often fix it yourself without needing a trip to the service center. I'd start with the simplest solutions first.
Remove Your Phone Case
Take the case off your POCO F6. Some cases, especially thicker or worn-out ones, can press against the buttons or prevent them from being fully depressed. It's a quick check that solves the problem more often than you'd think.
Perform a Force Restart
A force restart clears temporary software glitches that can cause the buttons to freeze. This is the most common fix for a sudden lack of response and won't delete any of your data.
For the POCO F6, press and hold the Power button for about 15 seconds. Keep holding it until you see the POCO or Xiaomi logo appear on the screen, then you can let go. The phone will boot up normally.
Clean the Volume Buttons
Dust and pocket lint are common culprits. The buttons on the POCO F6 have small gaps where debris can get stuck and prevent proper contact.
You can try blowing gently around the buttons or using a soft-bristled brush. For sticky residue, a cotton swab dipped in a tiny amount of isopropyl alcohol (90% or higher) can help. Just be careful not to push any debris further inside the phone.
Check for Software Updates
HyperOS updates frequently include bug fixes for hardware interaction issues. It's worth making sure your phone is running the latest software.
Go to Settings > About phone > HyperOS version. Tap on the "Check for updates" button at the top. If an update is available, install it while connected to Wi-Fi and, ideally, your 90W charger.
Test the Buttons in Safe Mode
Booting into Safe Mode temporarily disables all third-party apps. If your volume buttons work perfectly in Safe Mode, then a recently installed app is likely causing the conflict.
To enter Safe Mode, press and hold the Power button until the power menu appears. Then, press and hold the "Power off" option on your screen. A prompt to reboot to Safe Mode will pop up. Tap "OK".
If the buttons work here, restart your phone normally and try uninstalling apps you installed just before the problem started.
Inspect for Physical Damage
Take a close look at the volume rocker. Has the phone been dropped recently? Even a small dent or crack near the button assembly can affect its internal mechanism.
Gently press along the side of the phone. Listen for any unusual clicking or feel for any stickiness that wasn't there before. Physical damage usually means a repair is needed.
Use On-Screen Volume Controls
While you're figuring this out, you can still adjust your volume. The quickest way is to press the physical volume button once to bring up the on-screen slider, then drag it with your finger.
You can also adjust media volume directly from the notification shade. Swipe down from the top of your screen and use the volume slider there, making sure you've expanded the quick settings panel fully.
Try a Different Sound Profile
Sometimes, a specific sound mode or setting can interfere. Go to Settings > Sound & vibration. Try switching between Sound, Vibrate, and Silent modes using the toggle at the top.
Also, check that "Media volume" is not locked or set to zero in a way that overrides the buttons. Play a video or song and try adjusting the volume then, as some settings only apply to media playback.
Reset All Settings
This is a stronger step than a restart but won't delete your personal files like photos or messages. It will reset all your system settings (Wi-Fi passwords, Bluetooth pairings, ringtones, etc.) back to default, which can clear out a misconfigured option causing the issue.
Go to Settings > About phone > Factory reset. Tap on "Reset all settings" and enter your lock screen password if prompted. Confirm the reset and let the phone reboot.
Consider a Factory Reset
If you've tried everything else and it's definitely not physical damage, a factory reset is the last software option. This will erase everything on your phone, so you must back up your data first using Xiaomi Cloud or by transferring files to a computer.
After backing up, go to Settings > About phone > Factory reset > Erase all data (factory reset). Follow the prompts to complete the process. If the buttons still don't work after a fresh install of HyperOS, the problem is almost certainly hardware-related.