- Computer must be set up with ADB (Android SDK).
- Check whether your Android device settings for "USB Debugging" is enabled or active. Home-Apps-Settings-Developers options-USB debugging-check the box to enable.
- Install necessary drivers of your phone mode and use native USB cable.
1. Plug-in your device to your PC using your USB cable (works on Windows, Mac and Linux). Make sure that you have an active pattern screen lock.
2. Open command prompt (CMD) from start menu.
3. Type in "adb shell" then hit enter.
4. Type "rm /data/system/gesture.key" then hit enter.
5. After completion of process, you need to "Reboot" your Android device. Do not unplug the device from machine!
6. After successfully booting up the device, unplug it from machine. Done, now setup the new lock pattern.