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

NOTE: Before you factory reset your device, you can visit this thread for a guide on how to back up data, and this thread instructions on how to restore data. Note that data stored on the SIM and SD cards will not be deleted.

Factory Reset via Settings:

  1. Open “Settings
  2. Scroll to “Personal” and tap “Backup & reset
  3. Enable or disable “Automatic Restore” and “Back up my data
  4. Tap “Reset phone
  5. If your device is protected by a password / PIN / lock screen, enter it to proceed
  6. Optionally, select whether to “Erase SD Card” as well
  7. Tap “OK” to confirm

Factory Reset via Recovery:

NOTE: In case your phone freezes, crashes, or otherwise it prevents you from resetting it via Settings, alternatively you can try resetting the phone via Android Recovery. To access Recovery:

  1. First power Off the phone
  2. Press and hold “Power” and “Volume down” at the same time
  3. Once the phone vibrates, release “Power
  4. At the “hTC download menu”, release “Volume down” as well
  5. In the menu, press “volume down” repeatedly to navigate to and highlight “Reboot to bootloader
  6. Press “Power” to select the highlighted option
  7. Press “Volume down” to highlight “Boot to Recovery mode
  8. Press “Power” to confirm
  9. Once you gain access to the “No Command” screen, press and hold “Power” and “Volume down
  10. Once in Android Recovery, release both keys
  11. While in Recovery, press “volume down” to navigate to and highlight “Wipe data/factory data reset
  12. Press “Power” to select the highlighted option
  13. Highlight “Yes – delete all user data” and press “Power” to confirm
  14. Once the phone resets, ensure “Reboot system now” is highlighted and press “Power” one last time

Check for OS Updates:

NOTE: After you factory reset your phone, it’s recommended to keep the OS updated at all times. To check for new updates:

  1. Launch “Settings
  2. Scroll to and tap “About
  3. Tap “Software information
  4. Check if a new update is available. If applicable, follow the on-screen prompts to download and apply the available update. NOTE: the update process will require at least one reboot

See More: HTC Desire 555: Factory Reset via Settings/Recovery; Check for OS Updates