Hi, I just came across something very strange. We have here a large nested BTreeFolder2 tree, whose leaves contain ExtFiles, e.g. btreef_root/btreef2/btreef3/btree_leave. Many of these leave folders haven't been read since their creation, which could have been up to 3 years ago. During a data migration, which consists of a cut/paste operation of the ExtFile objects into another part of the tree (common root within the same zodb) I ran into a CopyError during manage_cutObjects. Looking for the offending objects in the ZMI didn't show me the leave folder, but calling .objectIds() on its parent did show its name. Also, the leave folder must be there somehow, because the operation is only attempted when its .objectIds() returns something. Accessing the "invisible" folder by direct url raises a NotFound. Condensed code of the migration: v0container = root.unrestrictedTraverse(['the', 'correct', 'path']) file_ids = v0container.objectIds() if file_ids: v1container = create_v1container(precalculated_path) v1container.manage_pasteObjects( v0container.manage_cutObjects(file_ids)) # boom so it seems unrestrictedTraverse() can do something which the ZMI doesn't. User roles contain Manager and Owner, I've tried running the script with Manager and Owner proxy roles. The same code on the same ZODB with the same user has worked some time in the past. Zope version: (Zope 2.11.6-final, python 2.4.5, freebsd8) I would appreciate any idea which data structure I should have a closer look at, to preferrably recover or delete these objects. best regards, knitti