I've heard off-list from someone who uses gretl on Mac about a nasty crashing bug, and I'm able to reproduce it. It seems to be (a) a GTK bug and (b) triggered only on El Capitan. To crash gretl: maximize a gretl window, then mouse up to the top of the screen to reveal the window controls and press the close button. The crash may not happen every time you do this, but in my experience it happens pretty reliably if you try a few times. It may also be possible to provoke the crash by using gretl in OS X's new Split View mode. Apparently gretl is not the only program to suffer from this. So, first, a word to the wise: to avoid data loss, it's best not to maximize gretl windows on El Capitan. Since gretl is not designed to run full-screen anyway that shouldn't be too much of a hardship. As for a fix, I'm working on it but it's tricky. The problem seems to lie in GdkQuartz, a component of GTK that's written in Objective C using Apple APIs. Objective C is, to me, a strange language bearing little resemblance to C, and I'm not at all familiar with the Apple APIs. But I'm hoping we can piggy-back off work done by others who are seeing this problem with their applications. Allin