vSphere Client does not open on any Windows operating systems with the error: parsing the server "<servername>" "clients.xml" file
注：2010.6.9 微软更新了.net framework。可能是load .net framework的工作机制改变了，
Symptoms
·        When trying to launch the vSphere Client you receive errors similar to:
Error parsing the server "<servername>" "clients.xml" file.
The type initializer for VirtualInfrastructure.Utils.HttpWebRequestProxy' threw an exception.
Resolution
You cannot use vSphere Clients prior to the Update 1 release, to access the vCenter Server or ESX hosts because of a Microsoft update that targets the .NET Framework (980773), released on June 9th 2010.  
 
Perform one of these two options to correct the issue:
1.    Download and install vSphere Client 4.0 Update 1 (build 208111) or Update 2 (build 258672) using method a or b below, depending on your environment.
a.    To download and install the vSphere Client for ESX, ESXi (paid version), and vCenter Server:
                                       i.        Go the downloads site.
Note: The vSphere Client .exe is part of the ESX, ESXi, or vCenter Server download binaries.
                                      ii.        Click Download next to your ESX, ESXi, or vCenter Server edition.
                                     iii.        Log in with your VMware Account credentials.
                                     iv.        Click Yes to agree to the EULA.
                                      v.        Click the .exe link next to vSphere Client and Host Update Utility.
Note: You do not need to download the entire vSphere suite, only the vSphere Client.
                                     vi.        Follow the on-screen instructions to install the updated vSphere Client.
b.    To download and install the vSphere Client Update 1 for ESXi (free version):
                                       i.        Go to the ESXi download site.
                                      ii.        Click Download.
                                     iii.        Log in with your account credentials, or register for free.
                                     iv.        Click Download next to vSphere Client and Host Update Utility.
                                      v.        Follow the on-screen instructions to install the updated vSphere Client.
2.    Remove the MS update from your Windows operating system. The vSphere Client works after the update is removed.
Note: This affects Windows XP, Windows 2003, Windows 2008, Windows Vista, and Windows 7.
 If the build number for your vSphere Client is 208111 or higher, then you have vSphere Client Update 1 or later, and should not be affected by this issue.
 
You can determine the version of vSphere Client by reviewing the build number located in the first line of a viclient.log file, located in %USERPROFILE%\Local Settings\Application Data\VMware\vpx on the system running the vSphere Client if the OS is Windows XP or 2003 and %USERPROFILE%\AppData\Local\VMware\vpx in 64 bit Windows 7 or 2008. Build 208111 or higher indicates you are using vSphere Client 4.0 Update 1 or later.
For example:
2010-05-19 03:08:58.508  Log for vSphere Client Launcher, pid=4756, version=4.0.0, build=build-208111, option=release
-------------------------------------------------------------------------------------------------------
 当然如果你不想升级vSphere Client也不是没有其他办法。见下面方法，同样来自官方。
This issue is resolved in VMware vSphere 4.0 Update 1. Prior to this update, the vSphere Client is not supported in Windows 7 or Windows 2008 R2 and it does not run in Compatibility Mode. This issue may occur because of the .NET loading mechanism change in Windows 2008 R2 and Windows 7.
 
You can download and install the VMware vSphere 4.0 Update 1 from the download page.
 
If you cannot upgrade to VMware vSphere 4.0 Update 1, there are 2 possible workarounds. Perform one of these options:
·        Using VMware Player or VMware Workstation, install a Windows XP virtual machine in Windows 7 or Windows 2008 R2.
·        Bypass the normal .NET Framework loading mechanism.
Warning: This workaround is unsupported.
To bypass the normal .NET Framework loading mechanism:
1.     Download the file system.dll. This file is typically located in  %SystemRoot%\Microsoft.NET\Framework\v2.0.50727\ directory of a non-Windows 7 or Windows 2008 R2 machine with .NET v3.5 SP1 installed.
2.     Copy the file to C:\Program Files (x86)\VMware\Infrastructure\Virtual Infrastructure Client\Launcher\lib.
Note: If the lib directory does not exist, create it.
 
3.     Open VpxClient.exe.config in a text editor. The file is located at C:\Program Files (x86)\VMware\Infrastructure\Virtual Infrastructure Client\Launcher.
4.     Add the following three lines to VpxClient.exe.config, just before </configuration>:
<runtime>
<developmentMode developerInstallation="true"/>
</runtime>
 
5.     From Windows 2008 R2 or Windows 7 System Properties, click the Advanced tab > Environment Variables. 
6.     Create a new System variable called DEVPATH and assign the value:
C:\Program Files (x86)\VMware\Infrastructure\Virtual Infrastructure Client\Launcher\Lib
Note: For 32bit operating systems, replace Program Files (x86)with Program Files.
You can now launch vSphere Client from a Windows 7 or Windows 2008 R2 machine. You may have to right-click on the vSphere Client icon and choose Run as administrator.