Unity Editor – [ERROR] FATAL UNHANDLED EXCEPTION

In RHEL, you might encounter this error, when trying to run the unity editor after (apparently) all dependencies are met.

Unhandled Exception:
System.TypeLoadException: Failure has occurred while loading a type.
at MonoDevelop.Startup.MonoDevelopMain.Main (System.String[] args) <0x40c2ce80 + 0x0000f> in <filename unknown>:0
[ERROR] FATAL UNHANDLED EXCEPTION: System.TypeLoadException: Failure has occurred while loading a type.
at MonoDevelop.Startup.MonoDevelopMain.Main (System.String[] args) <0x40c2ce80 + 0x0000f> in <filename unknown>:0

You might still be missing gtk2-sharp (required by Unity Editor), and gnome-sharp (requirement by the mono develop ide).

yum install gtk2-sharp gnome-sharp