Most of us have run into a hugely annoying bug with vSphere Client (a.k.a. VMware Virtual Infrastructure Client v4.0) running on Windows 7 RC. When you start the program, you’ll run into an error message:

Error Parsing the server 1.2.3.4 clients.xml file. Login will continue contact your system administrator

After clicking OK, you get the real message:

The type initializer for “VirtualInfrastructure.Utils.HttpWebRequestProxy” threw an exception

A workaround for the solution was posted by ftublo on the VMware Communities forums.

1. Create a folder (e.g. Lib) in the Windows 7 machine where the vSphere client is installed (%ProgramFiles%\VMware\Infrastructure\Virtual Infrastructure Client\Launcher\).
2. Obtain a copy of %SystemRoot%\Microsoft.NET\Framework\v2.0.50727\System.dll from a non-Windows 7 machine that has .NET 3.5 SP1 installed. Copy this file into the folder created in Step 1.
3. In the vSphere client launcher directory, open the VpxClient.exe.config file in a text editor and add a <runtime> element and a <developmentMode> element within the <configuration> element. Save the file.

<?xml version="1.0" encoding="utf-8"?>
<configuration>
...
<runtime>
<developmentMode developerInstallation="true"/>
</runtime>
</configuration>

4. Create a batch file (e.g. VpxClient.cmd) in a suitable location (e.g. Desktop). In this file add a command to set the DEVPATH environment variable to the folder where you copied the System.dll assembly in step 2 and a second command to launch the vSphere client. Save the file.

SET DEVPATH=%ProgramFiles%\VMware\Infrastructure\Virtual Infrastructure Client\Launcher\Lib
"%ProgramFiles%\VMware\Infrastructure\Virtual Infrastructure Client\Launcher\VpxClient.exe"

NOTE: If you are running 64-bit Windows, replace all instances of Program Files with Program Files (x86).

You can now use the VpxClient.cmd (or the shortcut) to launch the vSphere client in Windows 7.

This workaround bypasses the normal .NET Framework loading mechanism. Assembly versions found in the DEVPATH folder are not checked. Handle with care.