Hi list, I have a doubt about how to solve a problem in a system I'm doing, I'll start explaining the context: The application is Pier based, but it is not a CMS (well, at least not just a CMS), it adds functionality bu extending pier components and commands. There are some added data that should be persisted to file, in order to be able to rebuild the image and has backups and so on... And for consistency (and in a paranioc way, but needed because we are keeping money ammounts, etc.) we are also persisting commans executed by users, and then we are capable to rebuild the user account if something happens. For both persistency issues we are using SandstoneDB. Well, the problem is when I want to persist pier commands (not those created by us, but previous ones)... many has class references and Sandstone tries to persist them too (and then SystemDictionary, and then hangs). My approach to solve this problem is adding a couple of methods to PRCommand #toSandstone and #fromSandstone who changes class references for symbols and viceversa. But now I have other problem: not all the commands are so easy to solve :) For example, those related to PRChangeCommand, it has a dictionary (fields) with a magritte description... and again, a large set of not-recordable data. My questions is: how can I solve this problem? I can just serialize (with SIXX or binary) fields, but that does not ensure data integrity if I reconstruct it latter... or I can just manually get enough data to reconstruct ir manually when needed... but I'm not sure if this is a good approach or not. Any opinion? Thanks in advance, Esteban