As the title says:
Any ideas?
Same problem here.
And the code completion is not working. It doesn’t show all attributes and methods.
I have the same issue on Mavericks.
With the 4.2.2 i was using Xamarin Studio (Monodevelop 4.x) and i had the same problem.
I have found the solution : http://forum.unity3d.com/threads/210509-Unity-4-3-MonoDevelop-not-loading-solution-Install-again
Yep this worked for me too! thanks!