The same happened to me ... turn off the cell phone, press the home, block and volume - buttons. It will come out that you are going to modify or that there was an error and it gives you 2 options:
1: press volume + to continue
2: press volume - to restart the device. I chose the 2nd option. The phone restarts without deleting anything and the games look good. At least that's what I did and it worked for me and for the moment it does not fail.
If it works for you, please notify.