A factory reset is an effective, last resort method of troubleshooting for mobile phones. It will restore your phone to its original factory settings, erasing all your data in the process. Because of this, it's important to back up information before you do a factory reset.So you don't lose it all.

Factory Reset

WARNING! By factory resetting the device, you will delete all of the data located on the device’s internal memory, including custom ringtones and media files, contacts, downloads etc. Furthermore all settings will be restored to factory values but data located on the SD and SIM card won’t be affected.

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

Factory Reset via Settings:

1. Launch “Settings”
2. Access “Cloud and account”
3. Tap “Backup and restore”
4. Optionally, turn “Back up my data” and “Restore” ON or OFF
5. Return to “Settings” and tap “General Management”
6. Tap “Reset” > “Factory data reset” > “Reset”
7. In case your device is protected by a lock screen, enter your password/PIN
8. Tap “Delete all”

Factory Reset via Android Recovery:

NOTE: If your device prevents you from resetting it via the method above, you can try resetting the phone from Android Reovery.

1. Turn the phone off then press “Volume Up” “Power” and “Home” / “Bixby” buttons at the same time
2. Release the buttons at the Android screen and wait for access to Recovery
3. Next press “Volume down” repeatedly to navigate the Recovery menu and highlight “Wipe data/factory reset”
4. Press “Power” to select the highlighted option
5. Highlight “Yes – delete all user data” and press “Power”
6. Highlight “Reboot system now” and press “Power” one last time to confirm

Reset Network Settings:

NOTE: When resetting network settings, you will delete all of your saved Bluetooth and Wi-Fi connection, while network selection mode, data restrictive settings, and background sync settings will be restored to default.

1. Open “Settings” and go to “General Management”
2. Tap “Reset” > “Reset network settings”
3. Enter your lock screen password/PIN if needed
4. Tap “Reset settings”