Turn off your Galaxy S6
Press and hold down the Power, Volume up and the Home buttons together.
After the beautiful Samsung logo appears you should see a blue recovery text at the top.
Use the Volume up and down keys to scroll in the Recovery menu.
Mark the entry “Wipe cache partition” and start it with the Power button.
This process will usually take some seconds and the previously display menu will appear, after it finished.
Finish the process with “Reboot system now” and you done
try this!