When having a more frequent problem as listed below please click the link to jump to the corresponding section:

  1. Dealing with compilations issues when building Mono or bugs of Mono
  2. Problems when using Mono
    1. Can not compile my source
    2. Works under .Net but not on Mono

Issues compiling Mono itself

Since Mono is a large piece of software you must strictly follow the Compiling Mono-Article as it contains a good compiling-howto. Especially keep a close look at the requirements of mono and if they are met (e.g. libgdiplus).

Can not compile my source

When compiling your sources please bear in mind that Mono provides a C#-Compiler, mcs.
Most help request regarding the compilation of user software can be fixed by adding the proper references because only mscorlib.dll and System.dll are referenced by default.

To add references to additional assemblies, the -r:Assembly switch can be used:

mcs Source.cs -r:System.Drawing.dll -r:System.Windows.Forms.dll

More help can be found in the manuals of mcs:

man mcs

Works under .Net but not on Mono

Naturally this question is very hard to answer since it relies on the specific application trying to run on Mono. Please read Guide: Porting Winforms Applications or Guide: Porting ASP.NET Applications as they provide a good overview on how to run windows applications on Mono.