Reset Network Settings:

NOTE: By resetting network settings, all your saved Bluetooth and Wi-Fi networks will be deleted, and network selection mode, data restrictive settings, and background sync settings will be restored to default values.

  1. Open “Settings
  2. Go to “General management
  3. Tap “Reset” > “Reset network settings
  4. If the phone is lock screen-protected, enter your password/PIN to proceed
  5. Tap “Reset settings

Factory Reset

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

NOTE: Before you reset the device, you can check this thread for instructions on how to back up data, contacts, and media files, and this thread for a guide on restoring data.

Hard Reset via Settings:

  1. Launch “Settings
  2. Access “Sound and accounts
  3. Tap “Backup and restore
  4. Optionally, enable or disable “Restore” and “Back up my data
  5. Go back to “Settings” and access “General management
  6. Tap “Reset” > “Factory data reset” > “Reset device
  7. If your device is protected by a lock screen, enter your PIN/password and tap “Continue
  8. Tap “Delete all” to confirm

Hard Reset via Android Recovery:

NOTE: If your phone freezes, crashes, or otherwise prevents you from resetting it via settings, you can try resetting the phone from the Android Recovery menu.

  1. First make sure the phone is powered off
  2. Press and hold “Volume Up” and “Home” at the same time, then press and release “Power
  3. At the Android screen, release the button and wait for the Recovery menu
  4. Navigate the Recovery menu by pressing “Volume down” repeatedly
  5. Highlight “Wipe data/factory reset” and press “Power” to select the highlighted option
  6. Highlight “Yes – delete all user data” and press “power
  7. Lastly make sure “Reboot system now” is highlighted and press “Power” to confirm

See More: Samsung Galaxy J4: Factory Reset via Settings or Android Recovery