Could you provide the full callstack from the crash, ? Access violation errors usually involve a reference to a null pointer so there should be a way to fix this. Is this a code project or blueprint only?
Edit: If it’s the same callstack, it seems that other users having this issue previously found out that it was an issue with the math expression nodes they created. Could you try temporarily deleting any that you have prior to converting to see if they are causing the issue?