I'm having similar issue. I'm trying to use Converter 4 to convert/move "this machine" (which is Windows 2008 located on one ESXi server) to another ESXi server (without shutting down Windows during conversion). When I was using Converter 4 Beta this worked without problems but now after entering second ESXi host, login and password I see list of VM already located on this ESXi server and when I try to press Next I see "The session is not authenticated". This is for sure no timeout (5 seconds of waiting or less). Any idea what could cause this?

EDIT: I'm using Converter 4 build 146302. Both ESXi servers are 3.5 build 143129.

I've just tryed conversion where source is "VMWare Infrastructure virtual machine" and I had exactly the same error in the same conversion step (selection storage and virtual machine name). I've restarted both ESXi servers before conversion.

I´m having the same problem. New to the ESX product so i tried creating a new user and after that it worked a couple of times yesterday, but today it´s the same problem.

Check the date/time settings on the server your trying to convert, if for some reason they dont match the ESXi server, fix it and restart the VMWare converter agent.

It works now.  Using task manager I found there were 2 instances of the converter program running.  I cancelled both and then restarted the converter.  Thanks for all your suggestions.

I am having this same issue but this does not seem to fix it in my case.  Any other suggestions?