Hi Chris (and anyone else who can help), Hopefully you may be able to save my sanity. Querying a ZCatalog(2.3.1, running update thing made no difference), I'm getting the following error: type: exceptions.TypeError value: len() of unsized object sr = self.searchResults(kw) File "E:\Zope\2379A4~1.1\lib\python\Products\ZCatalog\ZCatalog.py", line 535, in searchResults (REQUEST,used, query_map), kw) File "E:\Zope\2379A4~1.1\lib\python\Products\ZCatalog\Catalog.py", line 651, i n searchResults used=self._indexedSearch(kw, sort_index, r.append, used) File "E:\Zope\2379A4~1.1\lib\python\Products\ZCatalog\Catalog.py", line 558, i n _indexedSearch append((k,LazyMap(self.__getitem__, intset))) File "E:\Zope\2.3.1\lib\python\Products\ZCatalog\Lazy.py", line 205, in __init __ self._len = len(seq) I inserted a print `seq` before that line, and the situations where it barfs, seq is either 461695167 or 0, rather than the list it should be. Has anyone else seen this? Anyone got a cleu what's going on or how I can find out what's going on? cheers, Chris