a downloaded sample Silverlight app gave me "ValidateXaml" task failed error

If you download a sample silverlight app and try to build it, and get below error

"Error The "ValidateXaml" task failed unexpectedly.
System.IO.FileLoadException: Could not load file or assembly 'file:///C:\MyTestingProjects\Silverlight4Upload\SilverlightFileUploadSrc\FileUpload\Bin\Debug\XX.XXXX.dll' or one of its dependencies.
Operation is not supported. (Exception from HRESULT: 0x80131515)
...
"

No need to try to de-bug it. This is simply because Windows protects you from downloaded files by default

Fixing this is pretty quick only if you know how/where to look. Below are the steps:

1.Right-click the downloaded zip file and choose “Properties”
2.At the bottom of the “General” tab, there is a “Security” section, saying “This file came from another computer and might be blocked to help protect this computer.” Click the “Unblock” button.
4.Unzip and open the solution.
5.Build, and the error message will go away!

Something good to note down for myself.