ok, its deffo to do with my data.fs cos the errors only start after that has been copied across. But the errors are different if i compare the console output from a failing 2.2.4 to a 2.2.0. If i do not install zdiscussions on 2.2.0 i only get the oid errors as items requiring display are requested from the database. with 2.4.4 i get the extra cannot import errors before zope starts regardless of whether zdiscussions are installed or not. something in zdbase is very different in 2.4.4. questions: 1. Will packing my data.fs help? I havent done this since well never. 2. Is the potential corruption of my data.fs likely to explode in my face without warning or is it/ will it only manifest itself during things liek product installs, upgrades etc? cheers Jonathan