Missing an alarm on your Xiaomi 15 Ultra can quickly turn into a stressful situation, especially when you rely on it for work, school, or important reminders. This issue usually happens because of system settings that silence alarms without you realizing it. The good news is that alarms rarely fail without a reason, and you can fix the problem by checking a few key areas.
Why Your Xiaomi 15 Ultra Alarm Is Not Going Off
- Alarm volume is set too low or muted.
- Do Not Disturb is blocking alarm sounds.
- Battery optimization is restricting the Clock app.
- The alarm sound is missing or corrupted.
- The phone powers down overnight due to low battery.
Make Sure Alarm Volume Is Turned Up
Alarms use a separate volume level that is different from media or ringtone volume. If this is set too low, your alarm may technically ring but stay silent.
Open Settings, and then tap Sound and vibration.
Tap Alarm volume, and then drag the slider to the right to increase it.
Test the volume by tapping the preview sound.
Check Do Not Disturb Settings
Do Not Disturb can block alarms if it is configured incorrectly. This often happens when custom schedules or exceptions are enabled.
Open Settings, and then tap Notifications and Control Center.
Tap Do Not Disturb, and then turn it off completely.
If you use it regularly, review the schedule and exceptions carefully.
Disable Battery Optimization for the Clock App
Xiaomi’s battery management is aggressive and may stop the Clock app from running properly in the background. This can prevent alarms from triggering on time.
Open Settings, and then tap Battery.
Tap App battery saver, and then find Clock in the list.
Set it to No restrictions so alarms can run freely.
Confirm the Alarm Sound Is Working
If the selected alarm tone is missing or corrupted, the alarm may fail silently. Changing the sound often fixes this instantly.
Open the Clock app, and then tap Alarm.
Edit an existing alarm, and then tap Alarm sound.
Choose a different default tone and save the alarm.
Make Sure the Phone Stays Powered On
Alarms will not ring if the phone shuts down overnight. Low battery levels or scheduled power off settings can cause this.
Open Settings, and then tap Battery.
Check battery level and disable any scheduled power off options.
Charge your phone before sleeping to avoid shutdowns.
Restart the Phone
A simple restart clears background glitches that interfere with alarms. It also refreshes system services related to time and scheduling.
Press and hold the Power key, and then tap Restart.
Wait for the phone to boot up fully.
Set a test alarm to confirm it works.
Once your Xiaomi 15 Ultra alarm is properly configured, it should go off reliably every time. Most alarm issues come from volume, battery, or background restrictions, and fixing those brings the feature back to normal quickly.
FAQs
Why does my Xiaomi alarm vibrate but not make a sound?
This usually means the alarm volume is set low or the selected sound file is not working. Increasing the alarm volume or choosing a new tone fixes it.
Will Do Not Disturb block alarms on Xiaomi phones?
It should not by default, but custom DND rules or schedules can interfere. Turning it off temporarily helps confirm if it is the cause.
Can battery saver really stop alarms from ringing?
Yes. Aggressive battery optimization can restrict background activity, which prevents alarms from triggering. Setting the Clock app to No restrictions solves this problem.
