Following a recent Cygwin update, I get segmentation faults when I try to plot graphs in Octave. Creating the figure window works (i.e. issuing the command "figure" doesn't cause the crash, it is only when plotting within the figure that I get a crash). I use the Octave command "sombrero" to test the plotting of data, but even simpler commands ("plot(1:10,1:10);") cause the crash. The crash occurs whether using the fltk or qt graphics toolkit. I'm using: Octave: GNU Octave, version 4.0.1 Cygwin: CYGWIN_NT-6.1-WOW OEM-9D7L362 2.5.0(0.297/5/3) 2016-04-11 09:55 i686 Cygwin The command I issue in Octave is: >> sombrero And I get this error message: >> panic: Segmentation fault -- stopping myself... attempting to save variables to 'octave-workspace'... save to 'octave-workspace' complete I ran strace to try to debug the problem. The strace output is too large (MB) to attach, but comparing strace for a normal termination of octave (run octave, create a figure but without plotting) and a segmentation fault termination of octave (run octave, issue command "sombrero"), I see that a segmentation fault causes "threads exited with status 0xc0000005". However I don't know how to debug this any further. I attach the output of cygcheck -s -v -r Any suggestions on how to debug this further or how to fix it would be very welcome! I have tried downgrading octave and qt but to no avail. Regards, Steve