To perform the master reset for an Alpha 100:
- Power off the device
- Press and hold your finger on the upper left side of the display
- Power on the device
- Wait to see Do you really want to erase all user data?
- Release your finger from the upper left side of the display
- Touch Erase
- Allow the device up to 20 minutes to acquire satellite data with a clear view of the sky
The device is now reset and ready for use.