Lollipop: alarm isn't firing in time After updating my Nexus 5 to Android 5.0 I noticed that alarm is not fired at set time (actually that spoiled my today's morning). 

When I set time for alarm it writes correct delta (e.g."Alarm set for 3 minutes from now"), but it doesn't make any sound or any on-screen changes in 3 minutes: the alarm just hangs in notification tray as an "Upcoming alarm".

I've checked the notification settings and didn't find any problem. but the notifications from Google Keep don't work as well...

What can be wrong with built-in alarm in Android L?
Well, I couldn't find the solution so I followed Ian Clark's advice and performed factory reset. That helped.