Hello, As mentioned in a previous mail, there seems to be a very serious bug with Export/Import and inheritance. Practically what happen is that when a class inherits from another class that belongs to another product, its exportation also include the class that it inherits. (have a look at the exported xml file to see the problem). Practically later after re-importing this class, its subclass is not the one that you see in your Zope browser, but rather a kind of "Ghost" class. Perhaps this apply also to your property inheritance bug to a certain extent ? (for instance, you may have had exported/imported when you had to upgrad your Zope installation). Thierry Nabeth INSEAD CALT http://www.insead.fr/CALT/