A factory data reset is a troubleshooting step usually done as a last resort to resolve some software issues.

This procedure restores all device settings and data to original factory defaults. All third party applications are also deleted.

NOTE: Ensure that personal data such as Contacts, Calendar, and preferred third party applications, is backed up prior to resetting.

You can do this by navigating to Settings > Accounts & Sync > Sync all.

To factory data reset using settings, follow these steps:

1. Navigate to Settings > Backup & Reset.
2. Select Reset Phone and confirm the selection.
3. Depending on the security settings on your phone, you may need to input a PIN or password.

To factory data reset manually, follow these steps:

1. Boot the device into the Bootloader (see How to use the Bootloader).
2. Navigate to and select Factory Data Reset. You may need to navigate and select YES after this step.
3. Select Reboot or Reboot System Now.