Thank you ABraun. The issue is now resolved. In manual it is written to type ‘L2A_Process.bat -help’, but when I typed, ‘L2A_Process.bat --help’, it worked without error. Earlier even if I had ignored this error and proceeded to use it for atmospheric correction, there was an error, and some files were empty in the resulting BOA product folder. The error was resolved with the successful processing of generating the BOA product by reducing the path of the input files (L1C).