I’ve just managed to up upgrade the SSO component of vSphere 5.5 in my lab after an hour of trying.
The issue I kept getting was 1603 error when it got to the LookupService part of the install. The result of the error was a rollback.
“Windows Installer installed the product. Product Name: vCenter Single Sign-On. Product Version: 126.96.36.1997. Product Language: 1033. Manufacturer: VMware, Inc.. Installation success or error status: 1603.”
In the end I changed the default site ‘Default-First-Site’ name to ‘Primary-Site’ and the rest of the install completed successfully.
Whether I had a bad SSO config to begin with will depend on if others get a similar issue. For the moment I’m posting this suggested workaround.