This will remove any temporary files that may be causing the problem, but will not delete your files or settings.
1. With the phone powered off, press the VOL DOWN KEY for 2-3 seconds then POWER key then release.
2. The Motorola XT390 will display different BOOT OPTIONS
3. Use the VOL DOWN Key to SCROLL to Recovery and VOL UP Key to select
Tip: If the Motorola XT390 reboots, you may have waited to long to make a selection, you will need to begin the process again.
4. The Motorola XT390 will display the Motorola logo and then the Android in distress ( logo with Exclamation mark)
5. Press and hold the VOL UP key for 10-15 seconds. While still holding the VOL UP key tap and release the POWER key
Tip: You can try this step, holding the phone in landscape. If you are stuck on step 6, try a force reboot by pressing the Power key and Vol Down key, and start the process again.
6. The Motorola XT390 will display additional menu options (Text will appear in BLUE)
7. Use the VOL DOWN Key to scroll to wipe cache partition and the POWER Key to select this option
8. The Motorola XT390 will then perform the partition wipe
9. The Motorola XT390 will reboot and start the normal power up sequence