From the beginning on my new unrooted and unflashed I9305 lost apps I had installed. I installed any app and it was runing normaly for a while and than it was gone and I had to install it again. I thought its a problem with Samsungs rom. So I decided to install a custom rom and choose ASOB Rom. But I'm still facing this problem. And it doesn't matter if the apps are installed fresh from the Playstore or from backup.