Screen lock password forgotten on Autel MaxiCheck MX808

I have an Android device as following: - Manufacturer: Autel - Model: MaxiCheck MX808 Automotive scanner tablet - Firmware Version: 1.0 I forgot the screen lock password. I communicated with Autel Tech Support on http://www.autel.com/ and they sent me a flash file and steps on how to flash, but I did not succeed. While I started ADB.exe, I got "Error unauthorized device". So please assist in resolving the issue. Ok steps I got from the support as follows MK Format Device Compulsively #### Set up Computer Circumstances 1. Install RK driver - Open the folder RK_DriverAssitant, run Driverintall.exe, following the on-screen prompts to install the driver. 2. Install Google-USB driver Some computers may need to install this driver. Open the folder Google-USB_driver; If your computer OS is 32-bit, run DPInst32.exe and if your computer OS is 64-bit, run DPInst64.exe. If you have already installed this driver before, please go directly to next step. #### Reflash the Device Attention：This procedure will format your device and will delete the data on your device. 3. Run Reflashing ToolOpen the folder AndroidTool_Release_v2.1, run AndroidTool.exe, the reflashing window will be displayed as shown in the figure below. 4. Turn Your Device into Reflashing Mode Connect your device to computer with USB cable and wait until the computer recognizes the device. You can check the connection status via Device Manager on your computer. As it is shown in the red mark on the figure below, the device was already recognized by the computer. 5. Ready to reflash: Double click on the script named reboot to loader.bat With best regards