SQL Server 2012 Express installation failed issue

I got an strange error when installing SQL Server 2012 Express

Environment:

Window Server 2008 R2 Enterprise + SP1

Microsoft Visual Studio 2012 installed

.Net 4.5 framework Installed

When I double clicked SQLEXPRWT_x64_ENU.exe, it just disappeared immediately, no setup window popped up. then I tried

1. unzip the installation code 

SQLEXPRWT_x64_ENU.exe /x

2. Open cmd.exe with administrator role

3. run setup.exe from command line, then I got error message

ERROR: Runtime error: This method explicitly uses CAS policy, which has been obs

oleted by the .NET Framework. In order to enable CAS policy for compatibility re

asons, please use the NetFx40_LegacySecurityPolicy configuration switch. Please

see http://go.microsoft.com/fwlink/?LinkID=155570 for more information.

looks like the error is caused by higher version of .Net Framework.

4. Uninstalled .Net 4.5 framework

5. rerun setup.exe, this time it worked as expected.

sometimes unzip the installation file and run from command line can get more detail error message, especially when you install hotfix and service patch.