Try this: On menu bar, click Project - 'SolutionName' Options - General - Allow 'unsafe' code -- View this message in context: http://mono.1490590.n4.nabble.com/Unsafe-code-on-MonoDevelop-2-4-2-OS-X-tp3640685p4659160.html Sent from the Mono - OSX mailing list archive at Nabble.com.