WARNING! By factory resetting your device, your personal data stored on the phone’s internal memory will be deleted. This includes ringtones and other media files, downloaded content, apps, contacts etc. Furthermore all settings will be restored to factory values but data located on the SD and SIM cards won’t be affected.

NOTE: Before resetting the phone, you can check this thread for a guide on how to back up data, and this thread for a guide on restoring data.

Factory Reset via Settings:

  1. Open “Settings
  2. Access “Phone Management
  3. Tap “Backup & Reset
  4. Clear or tick the boxes linked with “Back up my data” and “Automatic restore
  5. Tap “Backup account” and select the desired account
  6. Then tap “Factory data reset” and optionally choose whether to “Erase SD Card” as well
  7. If your phone is protected by a lock screen, enter your password/PIN to proceed
  8. Tap “Delete all” > “Reset

Factory Reset via Android Recovery:

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

  1. First turn the phone Off
  2. Press and hold “Power” and “Volume down” simultaneously
  3. At the LG screen, release and quickly press “Power
  4. At the “Factory data reset” screen, release the keys
  5. Press “Volume down” repeatedly to navigate the menu and highlight “Yes
  6. Press “Power” to select the highlight
  7. When prompted to “Erase all user data and restore default settings” highlight “Yes” and press “Power” again

See More: LG Harmony 2: Factory Reset via Settings or Android Recovery