Need to manage an old vCenter 5.5 host? Finding the legacy vSphere Client (C# client) is tricky. Here is the direct download link and a critical security warning.
Microsoft .NET 3.5 SP1 framework is required. Key Features & Limitations Capability in vSphere Client 5.5 Virtual Hardware vmware vsphere client download 5.5
Locate the version 5.5 archive. Note: Access may require a registered account with active or historical entitlements. Need to manage an old vCenter 5
Open a web browser and enter the of your ESXi 5.5 host. vmware vsphere client download 5.5