I have been looking into ticket 203 - Marshal.dump does not serialize an Exception's backtrace. It looks like the first reason is that dump is not currently exporting instance variables. Digging deeper, I found that MacRuby is not currently using the ID_INSTANCE tag for identifying instance variables. It doesn't look like instance variables are being identified as separate from other types right now. I am not sure which way to go from here. What are the plans for supporting instance variables? I would be happy to work on getting that support in if I had some direction. I am planning on working on the tickets and TODOs in the Marshal module and working out from there as I learn more about the MacRuby codebase and ObjectiveC/LLVM in general. So, this would be a good opportunity to delve deeper. Thanks! Jeff