why did my HTC one M9 reset itself

[AC Question]

all i remember was that my battery was low when i went to bed.
As i pick up my phone after waking up I realized it has reset all my config, most of the games, date and time. is there a way to fix this and make sure it does not happen?
unfortunately i only backup once a month.

 

[Andym9]

Mine done the same last night and had a low battery. Woke up in the morning and all contacts had gone apps had to start again.