I've recently begun getting the error "The remote computer requires Network Level Authentication, which your computer does not support." when trying to connect to a Windows 7 host that I recently made some changes to, including stopping/disabling many services and start-up applications whose purpose I do not know.
Two clients I have tried connecting with used to work connecting to this host, still work on Windows 2008 server computers and other Windows 7 hosts with NLA enabled, and show that they support Network Level Authentication in the about box (RDP 7.1, shell/control version 6.1.7601), so I am certain it is an issue on the host.
Is there a certain service or start-up application on the host that would cause this error? I've gone through the articles I've found and made sure 'credssp' is configured in the registry, really the only change I've made is stopping start-up apps and services but none of them seem to have anything to do with the process.
mstsc.exeon a client computer, click on the window control button (top left corner) and select "About". One of the lines in that screen will tell you explicitly whether or not NLA is supported. Shell/Control version and RDP version do not matter if the box says NLA is not supported. – Iszi Jun 26 '12 at 19:36