WARNING! When you factory reset your phone, all of your personal data stored on the internal memory will be removed, including media files, downloaded content, contacts etc. Furthermore all of the phone’s settings will be restored to factory values.

NOTE: Before applying the master reset, you can visit this thread to learn how to back up and restore data, and this thread for a guide on using HTC Sync Manager to sync data.

Factory Reset via Settings:

  1. While viewing the home screen, tap “Apps”
  2. Go to “Settings”
  3. Swipe to “Personal” and tap “Backup & reset”
  4. Enable or disable “Backup my data” and “Automatic restore”
  5. Tap “Reset phone”
  6. Assuming the device is protected by a screen lock, enter the password / PIN / pattern etc. and proceed
  7. Optionally, enable “Erase SD Card”. WARNING! This will delete all content stored on the SD Card
  8. Tap “OK”
  9. At the “Warning” pop-up, read the information and tap “OK”
  10. Your device will now perform the factory reset

Factory Reset via Hardware Keys:

NOTE: If you are unable to reset the phone using the method above, you can try resetting it by performing a combination of hardware button presses. To use this method:

  1. Turn off the phone
  2. Press and hold “Volume Down”
  3. With the volume key pressed, press and release “Power” to turn on the phone
  4. Keep holding “Volume Down” pressed until a black screen with blue and red lines of text appears
  5. From the aforementioned menu, press “Volume Down” repeatedly to navigate to and highlight “reboot to bootloader”
  6. Press “Power” to select the option
  7. In the next menu (should have a white background), use “Volume Down” to highlight "Boot to Recovery Mode”
  8. Press “Power”
  9. When the phone displays a red exclamation mark, hold “Power” and then press and release “Volume Up”
  10. From the “Android system recovery” menu, navigate to “wipe data / factory reset” using “Volume Down”
  11. Press “Power”
  12. Highlight “Yes – delete all user data” and press “Power”
  13. Lastly, with “reboot system now” highlighted, press “Power” one last time to reboot your phone

Check for Firmware Updates:

NOTE: After a fresh factory reset you should check and see if newer OS updates are available for download. To do so:

  1. Open the apps drawer
  2. Access “Settings”
  3. Scroll to “Phone” and tap “About”
  4. Tap “Software information”
  5. Check if a newer update is available. If yes, follow the on-screen prompts to install it

See More: HTC Desire 520: Factory Reset and Update the OS