''Unfortunately, Calendar Storage has stopped'' error on Sony Xperia M (C1905) I get "Unfortunately, Calendar Storage has stopped" because of  which I cannot make calls or send Email from my phone. This affects my work too. 

Is there a solution for this issue? I've already formatted my device because it was slow and lagging a lot.
First try rebooting 

Then try deleting app data from the calendar storage app preinstalled on your phone 

If this problem persists try reseting your phone again