While Broadcom has restricted many direct downloads for legacy products, you can still obtain the installer through several methods:

The short answer is:

ESXi 5.5 uses TLS 1.0 and weak ciphers (RC4, SHA-1) for its API connections. Windows 11, per enterprise security defaults (and soon, by mandate), has TLS 1.0/1.1 disabled at the SChannel level. Even if the client installs, it will fail to connect to any ESXi host because the handshake is rejected. Forcing insecure protocols requires registry hacks that compromise the entire OS.

The installer ( .exe ) was built for Windows 7/8. On Windows 11, you will likely encounter:

Official Distributor South Africa