o secure the device from unauthorised access, Samsung Galaxy has embedded many security options. Beside the usual Pattern or PIN Code lock, it is also possible to setup a startup password and encrypt the device. To activate this lock, do the followings:
1: Go to device Settings,
2: Navigate to Security,
3: From the Encryption section, select Encrypt device,
** It warns you that you will require a battery charge of at least 80% and that your phone is connected to the charger.
4: Tap the Encrypt Device.
**Do not forget that Encryption process could take around 1 hour to complete. (Depends on the amount of files on your phone)
**You need to enter the password, each time of starting up the phone
**The only way to remove this lock is to do a Reset Factory.