WARNING! When you factory reset your phone, all your personal information stored on the device’s internal storage will be deleted, including media files and ringtones, contacts, apps, downloaded content etc. Furthermore, all settings will be restored to factory values.

NOTE: To learn how you can back up and restore data before the reset, visit this thread. Data stored on the SD and SIM cards will not be affected.

Master Reset via Settings:

  1. Tap “Apps” on the home screen
  2. Launch “Settings” and scroll to “Personal
  3. Tap “Backup and reset
  4. Enable or disable “Back up my data” and “Automatic restore
  5. Tap “Factory data reset” > “Reset device
  6. In case your phone is protected by a lock screen, enter your PIN / password to proceed
  7. Tap “Continue” > “Delete all” to confirm

Factory Reset via Android Recovery:

NOTE: In case you are unable to reset the phone using the method above, alternatively you can try resetting the device from the Android System Recovery menu, which can be accessed by performing a combination of button presses.

  1. Turn off the device if necessary
  2. Press and hold “Power”, “Home” and “Volume Up” at the same time
  3. When the “Samsung” logo appears, release “Power
  4. At the “Android” logo, release “Home” and “Volume Up” as well
  5. You should now gain access to “Android Recovery Menu
  6. Press “Volume Down” repeatedly to navigate the menu and highlight “Wipe data / factory reset
  7. Press “Power” to select the highlighted option and confirm
  8. After the reset is complete, “Reboot system now” should be highlighted
  9. Press “Power” once last time to restart your phone

Check for OS Updates:

NOTE: After resetting the phone, it’s recommended to check if new software updates are available for download. To do this:

  1. Go to “Settings
  2. Scroll to and tap “About device
  3. Verify if a new software update is available
  4. If applicable, follow the on-screen steps to download and apply the update(s). NOTE: this require at least on reboot

See More: Samsung Galaxy C9 Pro: Master Reset via Settings or Recovery; Update the OS