MonoDevelop opens instead of Visual Studio

Hi,

I have Visual Studio 2010 Pro, and have set it to the external editor in unity, however when I open a script, it shows “Opening Visual Studio”, but it opens in MonoDevelop, not VS. I have tried reinstalling unity, but it didnt work.

Any Ideas?

Had the same issue. It seems when VS does take too long to start, Unity does launch MonoDevelop instead.

What did help is renaming “MonoDevelop.exe” to something like “MonoDevelop2.exe”

This was happening to me because I had Visual Studio set to “Always run as an Administrator”, but I didn’t do this for Unity. As soon as I made Unity also “Always run as an Administrator”, The problem was solved.

From http://forum.unity3d.com/threads/double-clicking-a-c-script-should-open-visual-studio.251358/#post-2431199

Have Visual Studio 2015 sp1. After upgrading from Unity 5.2.3f1 to 5.3.0f4 I began seeing this problem: “…started saying it was opening VS and opened Mono Develop instead…”
I upgraded to 5.3.1f1 and I am still seeing the same problem with an extra symptom:
Now Visual Studio must Migrate the project to the current Visual Studio version. While the version upgrade is in process, Mono Develop opens.
Other observations I see:
The VsHub.exe tree of processes gets started. (Looks normal)
devenv.exe gets started and just silently idles.
The new devenv (2015sp1) includes a child process named PerfWatson2.exe when started manually; the Unity kick off never includes this child process.

A workaround exists:
Manually open Visual Studio and open the Unity project. Now double clicking a file will open it in Visual Studio but the whole project has to be migrated each time… it appears Unity is not accepting the Visual Studio Migration changes.