Duncan at Yellow Bricks has a handy post on cleaning up your VI Client cached server address list.
There is a related issue with cached self-signed SSL certificate thumbprints. When you first connect to a VirtualCenter Server or ESX host, you see a dialog box:
By checking that box, the SSL certificate thumbprint is cached in your registry and you won’t be prompted again as long as there is a match.
If you ever want to take a quick look at the list, try this in a cmd window:
reg query "HKEY_CURRENT_USER\Software\VMware\Virtual Infrastructure Client\Preferences\UI\SSLIgnore" /s