The process of upgrading VirtualCenter includes several changes from the upgrade process in previous releases.

When you upgrade from VirtualCenter 2.x to vCenter Server 4.0 Update 1, consider the following:

The unified installer is no longer supported.

The autorun.exe executable file provides an HTML interface that presents the following installers:

vCenter Server

vCenter Guided Consolidation

vSphere Client

vCenter Update Manager

vCenter Converter

The database schema upgrade occurs before the upgrade to vCenter Server. This ensures that your existing version of VirtualCenter 2.x remains in place until the database schema upgrade completes successfully. When the database schema upgrade is successful, the upgrade to vCenter Server begins.

vSphere 4.0 Update 1 introduces the vCenter Agent Preupgrade Check tool, which helps ensure a successful upgrade to vCenter Server 4.0 Update 1.