The .sy file is a file that is created by the compiler for use by the debugger. It contains information that allows the debugger to deal with the program's data and code by the COBOL symbol names and actual source lines.
In the older versions of the compiler, you specified the -d and -s switches. In the current version, you create a .sy file by compiling your source with the -Z switch. Run "icobol -h" to get a list of command line switches to see which case applies.
Additional information about general system debugging can be found in the ICOBOL General Questions, in the group of questions for the task you were trying to perform when the problem occurs, or in the group of questions specific to your ICOBOL operating system (Windows or Linux).