There appear to be a lot of angry iPhone users out there who showed up late to work or school this week. 

The culprit appears to be a new software update that threatens to delete saved alarms, Heather Nauert reported on Fox and Friends this morning.

Apparently running the update overnight can cause the alarm to disappear by morning. 

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This is not the first time iPhone alarm clocks have malfunctioned. In 2011, a glitch with the application caused users around the world to miss flights or show up late to work for several days straight, reports.

The transition to daylight savings has also caused alarms to not work correctly in the past.

Frustrated users took to Twitter to share their accounts of oversleeping.