Reading Time: 4 minutes VMware Single Sign On is a new VMware vCenter Server components, introduced for the first time in vSphere 5.1, that manage the authentication across different VMware components both for services and users. It is not just an authentication broker but also a security token exchange providing a more secure way of accessing your vSphere solutions. For more information see also: vCenter Single Sign-On Part 1: what is vCenter Single Sign-On? This also mean that if you forget the SSO admin password you may have some trouble in your environment.