I have Samsung Galaxy S III Mini and its been recently turning on Wifi on and connecting to my home Wifi. If I turn Wifi on by myself, use some internet-requiring apps and then turn off Wifi and the screen, after a couple a minutes the Wifi is on again... If I'm on the move the Wifi just turns on but naturally can't connect to any secured Wifi networks. I've often cleared RAM memory and I also have a memory booster app (Clean Master). Any advice how could I prevent this from happening? It drains my battery in a day. Also, I live in Finland so Sprint's connection optimizer isn't the culprit.