The step can be found at http://support.t-mobile.com/docs/DOC-3803
Perform master reset
A master reset restores the original factory settings and may erase all downloaded content, including ringtones, images, programs, and contacts stored in the internal memory. It does not erase data stored on the SIM card or memory card (if available).
Note: Turn off Back up my data and Automatic restore to help avoid a recurrence of the issues you are attempting to resolve by performing a master reset.
To perform a hard reset, follow these steps.
Save any open files, and back up all necessary data on the internal memory.
- Back up all necessary data. See: Preparing for a master reset on Android.
- From any Home screen, tap the Menu key.
- Tap Settings.
- Scroll to and tap Privacy.
- Tap the Automatic restore check box to turn off, if desired.
- Tap the Back up my data check box to turn off, if desired and tap OK.
- Tap Factory data reset.
- Check/uncheck the Format USB storage, if desired.
- Tap Reset phone.
- Tap Erase everything.