Hi, I am currently testing 802.1x port authentication and experiencing a strange behaivor on my Windows 7 Client. My test environment: W2k8R2 with CA and NPS role Dell 5424 Switch Windows 7 Enterprise 64 bit The authentication (with user certificates after ad auto rollout) in general works fine but after a several times of logging off the client gets into a state where is does not respond to request packets from the switch (request, identify). The issiu occurs sporadically. I have found the following thread that describes exactly my problem, but I can not find any answers: "I have a Windows 7 Enterprise 64 bit installation that is having problems with 802.1X. It sometimes gets into a state where it does not respond to EAP Requests. If I disable then enable the interface, it will start responding to EAP Requests. I can get it into this state by logging off. In my case I do not have computer authentication configured. Which means that it fails. Then logging in again with the same user account that has worked previously, will get the system into an unauthenticated state. A packet capture show EAP requests coming from the switch but no response from Win 7. Any idea how to get it to behave correctly?" The following link describe my problem, too (http://support.microsoft.com/kb/980295). But the installation of the hotfix did not solve the problem. Thank you in advance! Best Regards