Error "HRPro version xx.xx does not match with database version yy.yy Unexpected result will be occurred!"

There is a message HRPro version xx.xx does not match with database version yy.yy Unexpected result will occurred! after HRPro Login.

Reason: 

The program version did not match the database version. It is usually due to

1. You are running an old program file (the up-to-date program file should locate in the HRPro shard folder in the file server, not c:\Program Files)

2. The last upgrade process is not completed.

3. The program file is accessing an out-of-date database (i.e. Database did not upgrade).