Issue: Unable to add Entity data model to a Visual Studio project.
While adding the Entity data model to your Visual Studio project, you may get the following error message:

Could not resolve mscorlib for target framework '.NETFramework,Version=v4.0,Profile=Client'

Error Dialog:
Microsoft Visual Studio
Could not resolve mscorlib for target framework '.NETFramework,Version=v4.0,Profile=Client'.  This can happen if the target framework is not installed or if the framework moniker is incorrectly formatted.

This error message appears due to corruption of ADO.NET entity model.  Apparently, the Entity data model is installed by the “ADONETEntityFrameworkTools_enu.msi”.

This installer for ADONETEntityFrameworkTools  can be found at the location:

<path to Visual studio Disk>\WCU\EFTools\ADONETEntityFrameworkTools_enu.msi".

Resolution: To fix this issue:

#) Remove the ADO.NET entity model by using the msiexex /x ADONETEntityFrameworkTools_enu.msi

#) Reinstall it with the command line:
msiexec /i ADONETEntityFrameworkTools_enu.msi USING_EXUIH = 1.


Content by : Keshav Jain