I know, you should not followup to your own message, but I wanted to give some additional information I just found. Trying to pinpoint the place, where the System is blocking, I inserted sys.stderr.write commands all over the ZServer/meduse code. By patching ZServer.PubCore.ZRendezvous.ZRendezvous.__init__ and ZServer.PubCore.ZServerPublisher.ZServerPublisher.__init__ I found, that the last method is *never* executed, when I run with ZEO. I really don't understand that. ZRendezous just creates a bunch of threads all running the ZServerPublisher.__init__ function. I cannot find *any* reason, why the threads should refrain from running ... just because ZEO is used ??? This sounds really weird in my ears, but maybe someone with a better brain than mine can help out ? Stefan. -- Stefan Bund, Dipl.Phys. a r T e c _____ Entwicklung, Administration visual solutions / | /| |----/_| sbund@artec-berlin.com | / | / Fon: 030 / 884684-0 | Fax: 030 / 884684-15 |/___|/ Gottfried-von-Cramm-Weg 35-37 | Berlin | 14193 | http://www.artec-berlin.com