Hi, I'm using Zope 2.6.1b1 (but the same behavior is exhibited by 2.6.0) and IE6 on XP. Before I spend a long time debugging this I thought I'd ask the list: Either IE's cookie handling (doubt it, since I tried this with highly permissive privacy settinngs) or Zope's browser id manager, or Zope's session manager or Zope's transient objects folder is misbehaving. Symptom: Session data is periodically and intermittently lost within a period of time much much shorter than the transient object timeout. To test this I use a single IE window reloading the very same "test.html" ZPT that simply checks for the existance of the key 'foo' in REQUEST.SESSION and reports the result (and sets it to 1 always). Preliminary evidence is that the problem is exacerbated by concurrent request handling. I test this using a windows client that utilizes the WinHTTP COM+ object to generate requests running on a separate machine (no chance of IE stepping on itself). Of possible relevance is that external python methods are invoked to fulfill the WinHTTP generated requests. Any initial hints on where to look? Thanks, Andrew Athan