Backup file created by some Android phones and other Android mobile devices; created through the advanced startup mode when pressing and holding the power button and volume button and then choosing the option to backup user information; saved to the Android device's SD card when the backup is complete. To restore a BACKUP file, hold the power button and volume button and choose the option to restore user information from the startup menu. BACKUP files contain user information such as contacts and user files. They are useful for archiving save points from your mobile device so that the data can be restored if there becomes a problem with the device.