WARNING! When you factory reset your phone, all your personal data located on the device’s memory will be deleted, including media files, ringtones, contacts, downloaded content, apps etc. In addition, all settings will be restored to factory values but data located on the SIM and SD cards won’t be affected.

NOTE: You can check this thread for a guide on how to back up data, and this thread for instructions on restoring data.

Factory Reset via Settings:

  1. Launch “Settings
  2. Go to “Phone Management” > “Backup & Reset
  3. Tick or clear the check box associated with “Back up my data” and “Automatic restore
  4. Tap “Backup account
  5. Select the account you want to use for the backup
  6. Tap “Factory data reset
  7. Optionally, choose to “Erase SD Card” as well
  8. When ready, tap “Reset phone
  9. If your device is protected by a lock screen, enter your PIN/password to proceed
  10. Tap “Delete all” > “Reset

Factory Reset via Android Recovery:

NOTE: If your device crashes, freezes, or otherwise it prevents you from resetting it using the method above, alternatively you can try resetting the device from the Android Recovery menu by following these steps:

  1. First turn the phone Off if necessary
  2. Then press and hold “Power” and “Volume down” at the same time
  3. At the LG screen, quickly release and re-hold “Power
  4. Release the buttons at the “Factory data reset” screen
  5. Then, press “Volume down” repeatedly to navigate the menu and highlight “Yes
  6. Press “Power” to confirm
  7. When prompted to “Erase all user data and restore default settings” highlight “Yes” and press “Power” one last time to confirm

See More: LG K8+: Factory Reset via Settings or Android Recovery