I Had Unity 4.0.x, then tried to update to 4.1.x, suddenly MonoDevelop stopped working. It just doesn’t open and brings a very weird window error.
Then I reverted back to Unity 4.0.0, eventually updated to Unity 4.0.1, all without issues… Now Unity 4.2 was released and I finally decided to try and update. Same issue.
What’s going on Unity Team? Why isn’t this solved yet? How could you even let this to happen?!
At the very bottom of Unity 4.2 release notes:
MonoDevelop may fail to start correctly on Windows if an old version of Gtk# is installed on the system. Please uninstall this version, and install a newer one if still needed.
GTK# has been the problem, and uninstalling it has been the “solution”, at least since Unity 4.1.4.
In my experience, updating GTK# to latest version (2.12.10) wasn’t good enough. But uninstalling it was an instant fix.
P.S.: Really, I just wanted to feed unityAnswers here. Did I mentioned already I hate forums?