There is no official, supported installer for the legacy VMware vSphere Client 5.5 on Windows 11.
The Official Source: You should ideally download the client directly from your ESXi host. If you have an ESXi 5.5 host running, navigate to its IP address in a web browser. There is usually a link on the landing page that says "Download vSphere Client." vsphere client 5.5 download for windows 11
Windows 11 is built on strict security requirements, such as TPM 2.0 and updated driver models. vSphere Client 5.5, a C#-based desktop application, was designed for much older versions of Windows and often struggles with modern high-DPI displays and newer driver signatures. How to Obtain the Client There is no official, supported installer for the
https://<Your_vCenter_IP>/vsphere-client/Registry Fix (SSL/TLS): Modern Windows versions might have older TLS versions (required by vSphere 5.5) disabled. You may need to manually add required cipher keys like TLS_RSA_WITH_AES_256_CBC_SHA in the Windows Registry to allow the connection. Critical Considerations Warning: Do not reboot
Since VMware (now Broadcom) has removed many legacy downloads from their main portal, the most reliable way to get the installer is directly from your server.