I am trying to use SandstoneDb to save an Object that contains a SortedCollection, but it fails with the error: "This message is not appropriate for this object". Here is an example code. SDActiveRecord subclass: #User instanceVariableNames: 'sorted name' classVariableNames: '' poolDictionaries: '' category: 'Sandbox' User>>initialize super initialize. sorted := SortedCollection new. name := 'asd' and of course accessors for both of my variables. I type this into a workspace: (User new name: 'david') save. User find: [:u | u name = 'david'] And it works correctly, but this errors with: "This message is not appropriate for this object" | u | u := User new. u name: 'david'. u sorted add: 1. u save What can I do to fix this? David Zmick /dz0004455\