OS X Update, X11, and XQuartz

I do all of my circuit design and layout as well as some software development by running X11 on a Macbook Pro that’s about 3-4 years old (Snow Leopard.) The basic flow involves logging in to a server at work from the “Terminal” application using:

ssh -Y -C servername

This automatically starts X11 and forwards graphical content from the server to my display. Yesterday, I ran software update for OS X and quite a few things were installed, including some operating system fixes. Immediately after, trying to run anything in X11 became impossible!  After a few minutes, it would crash completely and just disappear. A quick search gave me some answers……  apparently, there are some dependency issues between Leopard and X11. When you update one, it breaks the other. In addition, it seems that there is a completely new X system used in Snow Leopard called XQuartz. After running the update, XQuartz on my machine was for some reason replaced with a broken version of X11. The only reason I knew this was because the two have very different icons:  XQuartz is on top, X11 on the bottom.So I needed to somehow get XQuartz back as the default display when running SSH with forwarding.  The solution more or less took care of itself. Just go to the XQuartz site, download a new installer, and run it.  Then restart. Everything will be back to normal, no more crashing……. until the next OS X update.