MonoDevelop wont open, Unity5, mac

I have unity5 on the mac and when I go to edit a script the MonoDevelop icon pops up in the dock, and after a few secs it disappears so the script editor never opens! It does this from the first day that I downloaded unity. I haven’t written a single script in unity!

I had the same issue yesterday; my first partition on my harddrive was filled up, so I installed unity on my secondary partition (the one that is not the system partition) and I could not open monodevelop.

I deleted unity on the secondary partition, made free space on the primary partition, installed unity (on primary partition), and now monodevelop opens fine.

Don´t know if this helps, but in my case it seemed unity & monodevelop did not like being installed on the secondary partition.