I have a failing test in my computer when running the test mentioned in the subject, I get the following error: "PGConnection has a defective state machine" Stack: PGConnection(Object)>>error: PGConnection(PGActiveObject)>>stCantHappen: PGConnection>>stCantHappen: PGConnection(PGActiveObject)>>processEvent: PGConnection(PGActiveObject)>>generateEvent:to: PGConnection(PGActiveObject)>>saProcessEventsUntil: PGConnection>>copy:withStream: TestPGConnection>>testNotify2 I tested in my computer with Pharo4, Pharo3 and Pharo2, and I get the same error in all the images with the latest version of it, and also with the oldest I could load (in Pharo 2, Name: PostgresV2-Maiano.24). My PostgreSQL server version is 9.3.7. Does it fail for you too? Regards! Esteban.