OK, so it seems a lot of people have had this issue except most of the solutions people have come up with haven’t worked for me. (I’m using windows 7 by the way). I’ve gone through the solutions in this link but to no avail: Monodevelop not opening in Unity 4.3 - Unity Answers
So I originally installed Unity 4.5.1 and when I tried to double-click on a script, the launcher for monodevelop pops up, and then disappears without actually opening the main program properly. If, I then go into task manager I can find monodevelop in my processes tab, and if I try double clicking on a script a few times, multiple entries appear in this task manager list. I have tried ending each process and trying again, but the same thing happens.
I then uninstalled unity, and went through my computer and manually deleted all unity folders (which was also where my monodevelop folders were contained within). And then reinstalled unity and restarted comp.
Same issue.
I then went to edit->preferences->external tools and changed the debugger from Monodevelop (inbuilt) to the Monodevelop.app in the bin folder.
Same issue.
I then tried to replace the file glibsharpglue-2.dll in my bin folder with a new one, except I couldn’t get permission to do this no matter what I did.
I then pressed start, typed out monodevelop and clicked on the .exe file and the same thing happened except I was also met with the following message (attached pic).
Please also examine the tests people have suggested below, as they have been fruitless so far.
Could someone please tell me how I can get monodevelop working normally again? I don’t want to have to use other IDEs as I’m super fond of monodevelop.