Solution: update to MonoMac 2.4.2. I was using 2.4.0.13 and when I upgraded (they just released 2.4.2 yesterday) everything worked! -- View this message in context: http://mono.1490590.n4.nabble.com/Unhandled-error-in-packaging-tp3228822p3256191.html Sent from the Mono - OSX mailing list archive at Nabble.com.