vSphere4 client failed to login after MS patch

[What's the issue?]

 

vSphere 4 client cannot login with error message:

Error parsing the server "" "clients.xml" file.

The type initializer for VirtualInfrastructure.Utils.HttpWebRequestProxy' threw an exception.

 

After Microsoft .net Framework security patch KB982168 (KB980773 within that patch), we have the above issue to login VC or ESX.

 

[What's the root cause?]

Microsoft enhanced security in .net Framework (System.dll) and results old vSphere client login failed with related files.

 

[What's the solution?]

1.) Upgrade the vSphere client to the latest version (officially it is 4.0 Update

 

To download and install the vSphere Client for ESX, ESXi (paid version), and vCenter Server:

Go the .

 

To download and install the vSphere Client for ESXi (free version):

Go to the .

   
2.) Remove MS patch for .net Framework

    KB982168 and KB980773

 

[Appendix]