The (formally the VMware vSphere Client ) was the primary Windows-based desktop application used to manage ESXi hosts and vCenter Server instances for over a decade. While it was the industry standard during the vSphere 4.x and 5.x eras, it has since been replaced by modern web-based interfaces. The Legacy of the VMware VI Client
With the release of , VMware began phasing out the viClient in favor of the vSphere Web Client .
In the early days of virtualization, the "VI Client" (Virtual Infrastructure Client) was a required C#-based application that administrators installed on their local Windows machines to perform nearly every administrative task.
While VMware's official blog is great, the community often provides the "real world" fixes. The most reliable external source for vSphere Client deep dives is .