The VMware SSL thumbprint feature addresses a frequently-reported error when creating a host connection to a VMware vSphere hypervisor. Previously, administrators had to manually create a trust relationship between the Delivery Controllers in the Site and the hypervisor's certificate before creating a connection. The VMware SSL thumbprint feature removes that manual requirement: the untrusted certificate's thumbprint is stored on the Site database so that the hypervisor can be continuously identified as trusted by XenApp/XenDesktop, even if not by the Controllers.
When creating a vSphere host connection in Studio, a dialog box allows you to view the certificate of the machine you are connecting to. You can then choose whether to trust it.