I deploy without a .changes file, but the image still compiles code at runtime. The methods are just accessor methods, and no image save is ever done. Using Pharo-2.0 (instead of Pharo-1.4), I now get a walkback: VM: unix - i686 - linux-gnu - NBCoInterpreter NativeBoost-CogPlugin-EstebanLorenzano.18 uuid: a53445f9-c0c0-4015-97a3-be7db8d9ed6b Mar 13 2013 NBCogit NativeBoost-CogPlugin-EstebanLorenzano.18 uuid: a53445f9-c0c0-4015-97a3-be7db8d9ed6b Mar 13 2013 git://gitorious.org/cogvm/blessed.git Commit: 412abef33cbed05cf1d75329e451d71c0c6aa5a7 Date: 2013-03-13 17:48:50 +0100 By: Esteban Lorenzano <estebanlm@gmail.com> Jenkins build #14535 Image: Pharo2.0 [Latest update: #20593] CompiledMethod(Object)>>doesNotUnderstand: #copyWithTempsFromMethodNode: CompiledMethod>>putSource:fromParseNode:inFile:withPreamble: ... It seems that #putSource:fromParseNode:inFile:withPreamble: calls #copyWithTempsFromMethodNode:, when there is no .changes file, but that method is not in the image. Is it safe to just patch the code to do nothing? The method comment says that the method temp names are saved for decompilation.