A call to C$SYSTEM fails when the command contains special characters like ‘&’:

CALL "C$SYSTEM" USING "START C:\\TEMP\\MF&2019.XLSX" 225
                GIVING RETURN-VAL

The following error is received. Only part of the command is recognized so the file cannot be found:

C:\\TEMP\\MF
Windows cannot find 'C:\\TEMP\\MF'. Make sure you've typed the name correctly, then try again.

Full article: https://portal.microfocus.com/s/article/KM000007308