Here's a tip that might get you a core file usuable for gdb: In your cygwin.bat add the error_start directive to the CYGWIN environment variable set CYGWIN=error_start=c:\cygwin\bin\dumper.exe Core files produced by dumper can be somewhat messy and unreliable in cygwin because processes are run as child threads. Even better, unless you're running unattended of course, you can have gdb automatically start up and attach itself when you crash. set CYGWIN=error_start=c:\cygwin\bin\gdb.exe