Zte Grand X User Manual page 25

If you change your mind about encrypting your phone, touch
the Back Key.
WARNING! If you interrupt the encryption process, you will
lose data.
3. Touch Encrypt phone.
4. Enter your lock screen PIN or password and touch Next.
5. Touch Encrypt phone again.
The encryption process starts and displays its progress.
Encryption can take an hour or more, during which time your
phone may restart several times.
When encryption is complete, you're prompted to enter your PIN
or password.
Subsequently, you must enter your PIN or password each time
you power on your phone, to decrypt it.
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