Using the Raspbian Wheezy image...

I installed the mono runtime like so on my Raspberry PI:

sudo apt-get update
sudo apt-get install mono-runtime

and it seemed to install fine (If I run mono I get a sensible command output).

Then I started MonoDevelop up up my mac and created a "Hello World" console application (you know, just what you get when you go New Solution | Console Application) - compiled and ran - no problem.

Now I copied the exe over to the PI and was expecting that I could just go:

mono HelloWorld.exe

but when I do so I get this error:

The assembly mscorlib.dll was not found or could not be loaded. It should have been installed in the `/usr/lib/mono/2.0/mscorlib.dll' directory.

Now I am confused - what have I done wrong and how should I get that DLL? Is there another package I should install?

  • What version of .net is is targeted for. It should not be pipelined either.
    – Piotr Kula
    Oct 26, 2012 at 9:06
  • Do you have that file (/usr/lib/mono/2.0/mscorlib.dll)? Do you have anything at all in /usr/lib/mono? Oct 26, 2012 at 10:55
  • @ppumkin - I am targeting "Mono / .NET 3.5"
    – kmp
    Oct 26, 2012 at 11:35
  • @SteveRobillard - That worked - thanks!! Maybe post it as an answer and I will accept it
    – kmp
    Oct 26, 2012 at 11:35

2 Answers 2


You need to install the mono-complete package (which includes the mscorlib.dll file); to do this enter the following at the command line.

sudo apt-get install mono-complete

In my case I was writing the wrong name of the HelloWord.exe file. When I wrote correctly i.e. mono Helloword.exe, it worked fine. However the error was the same one

  • 1
    If mono HelloWord.exe report some missing dll, the problem is somewhere else.
    – mpromonet
    Feb 23, 2015 at 19:52

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