Thank you for your reply. I uninstalled all and reinstall (gretl 1.9.90(Mac OS X(quart, x86 64)), but still the problem continues. Interestingly, it produces graph for the file attached below (Ass_2014_s1.gdt) but the second file (tuna_ass_2014s1.gretl) it won’t produce any types of graph. for example I try produce a scatter plot for variables SB1 and PB1 but it shows the error message with black colour screen.Any advise on this. i highly appreciate it.