WARNING! When you master reset your phone, all your personal data located on the device’s internal memory will be deleted. This includes downloaded content, media files, ringtones, applications, contacts etc. Furthermore, all settings will be restored to factory values. However, data stored on the SD and SIM cards will not be deleted.

NOTE: Before you master reset your device, you can visit this thread for instructions on how to back up data, and this thread for instructions on how to restore data. In addition, you can visit this thread for instructions on how to back up and restore data via HTC Backup or locally.

Factory Reset via Settings:

1. Open the apps drawer
2. Go to “Settings”
3. Scroll to “Personal” and tap “Backup & reset”
4. Turn “Backup my data” and “Automatic restore” On or Off
5. Tap “Reset phone”
6. If your phone is protected by a lock screen, enter the necessary password / PIN to proceed
7. Optionally, select whether to “Erase SD Card” too. WARNING! By enabling this option all data on the SD card will be deleted during the reset process
8. At the “Warning” pop-up, tap “OK”, and then tap “OK” to confirm and start the reset
9. Wait for the device to reboot

Factory Reset via Recovery:

NOTE: If your phone freezes, crashes, or for other reasons you are unable to reset the device via Settings, you can try factory resetting the device from the Recovery menu instead. To access Android System Recovery, you need to perform a sequence of button presses.

1. First, make sure the phone is turned off
2. Next, press and hold “Volume down”
3. Press and hold “Power”, and release the button once the device vibrates
4. When you gain access to “hTC download mode” release “Volume down” too
5. Press “Volume down” repeatedly to navigate the menu and highlight “reboot to bootloader”
6. Press “Power” to select the highlighted option
7. Press “Volume down” to highlight “Boot to recovery mode” and press “Power”
8. When an exclamation mark appears on the display, press and hold “Power”, and press & release “Volume Up”
9. After you gain access to the “Android system recovery” menu, release all buttons
10. In the recovery menu, press “Volume down” repeatedly to highlight “wipe data / factory reset”
11. Press “Power” to select the option
12. After the reset is complete “Reboot system now” should be highlighted
13. Press “Power” one more time to confirm and reboot your phone

Check for Software Updates:

NOTE: After a new factory reset, it’s recommended to check if new software updates are available for download. To do so:

1. Open the apps drawer
2. Go to “Settings”
3. Scroll down to “Phone”
4. Tap “About” > “Software information”
5. Check if a new update is available and if necessary, follow the on-screen instructions to download and apply the update