KEIL can not display existing *.c or *.h source file with a blank TEXT

Hi All:

      My KEIL is 5.38A.

      My OS is Windows 10 X64 2022H2 CHS version.


      When I select the compiler version as 6.13 or 6.19, then 

      My KEIL project sometimes can not open a existing *.c or *.h file, it displays a blank text in the editor window.

      If fact this file is NOT blank, it can be successfully opened by many other TEXT editors


      When I select the compiler version as 5.06, then this problem seems disappear!

      Then what's wrong with my KEIL IDE?

      How should I fixed this issue?

      If you need any further information, please let me informed!

      Thanks & Best Regards