MonoDevelop Issues with Unity

Hey.
I've been having some issues that I ignored, but I think it's time to get rid of them.

1. Whenever I double-click on a script file in unity, it seems like a new MonoDevelop instance is loaded, rather than just open the script in the existing MonoDevelop.
2. I keep having these reference errors when I open MonoDevelop (or after opening a new script file from Unity).

I might have some more I am forgetting. I'll post screenshots later today if it is unclear what I am referring to.

Thanks for the help.

 

I suggest just re-installing MonoDevelop, if you haven't already.

 

I've been having some similar issues to what you're describing, I'm on a Mac and I do have multiple instances of Unity installed (4.5.3f3 and 4.6.0b18) for work purposes. I've found that deleting the additional MonoDevelop versions and shifting one version of MonoDevelop out of the Unity folder to Applications fixes the issue of multiple instances being opened (changing the target location in Unity's preferences doesn't fix it), which mind you has never been an issue in the past. However MonoDevelop still won't link/attach to Unity correctly, it still warns me of syntax errors and the like, but double clicking the error in the debug log only opens MonoDevelop, it no longer takes me to the line within the class containing said error. On top of that I can't even open Shader files through Unity anymore, the debug log just spits out disingenuous warnings claiming that it doesn't know what Shaders are.

I have tried reinstalling both Unity versions multiple times, tested to see if the problem persisted with only one version installed, tried deleting the MonoDevelop preferences folder, and even attempted updating to the latest version of OSX hoping that doing that may somehow magic away the problem, none of that has proven to fix anything though.

Anyway, if anyone has a solution that isn't completely stupid (like performing a clean OS install) I'd be very happy to hear it.

TL;DR: MonoDevelop won't open correct solution (.sln) when scripts are double clicked in Unity, Unity won't allow shaders to be opened in MonoDevelop, and double clicking on an error will only open MonoDevelop if it isn't already. I've tried multiple different potential fixes, none of them have worked.