Autel MaxiSys MS908P Cannot Communicate after Upgrade (Solved)

Autel MaxiSys MS908 or Autel MaxiSys MS908P automotive diagnostic scanner can not communicate and diagnose vehicles after upgrade problem solution provided.
Problem:
One of the Autel MS908 scanner users has newly got the scan tool updated software he need to latest version, but the newly upgraded Maxisys system can not communicate/access to car.  So He decided to run an upgrade again.
But the device prompted it is the latest version. Then He tried to diagnose other models. He followed the system instruction to turn ignition switch to ON position, but the device still prompted turn ignition on and fail to communicate and diagnose any cars.
Possible reason:
Incorrect update procedure or did not upgrade software completely.
Solution:
Note: The solution fits Autel Maxisys MS908 Pro from CnAutotool.com as well.
Un-install all upgraded software
Come to Autel MS908 diagnostic scanner main unit, select “Data Manager” function

3) Select “Apps”

4) Delete upgraded software

5) Download and update the vehicle software you need again, wait the procedure completed.

6) Re-connect the Autel Maxisys MS908P with vehicle and perform diagnosis.