I have upgraded Alfresco CE from version 3.0 to version 3.3g.
Everything works fine but one thing: I have had created some categories and subcategories in my old system.
After upgrading in Explorer everything is fine - I can see and use all of my categories. But in Share I can see the categories-tree correctly, but I cannot expand the first node. The second node and all of the rest I can expand and use without any problem. I thought the first node (directory) of categories is broken, but - as I stated above - in Explorer everything is good.