Issue

When trying to authenticate, and convert machines within your VMware convertor you recieve the following error :

       The session is not authenticated

Fix

Within windows go into your task manger and kill all of your VMware convertor processes that are currently running.

Reference

http://communities.vmware.com/thread/195575

Still have Issues ?

If this has still not resolved you issue you may want to look here : http://www.fir3net.com/VMware/ESX/esx-convertor-the-session-is-not-authenticated.html