I wasted several hours after creating the project on my u: drive.
The problem was fixed when I moved the project to my c: drive.
The compiler generated a dll. The debugger complained when I tried to run the project. Here's the error that I received.
By the way, the page in the error message suggests that you disable security. I did not try that.
C:\Program Files\MSBuild\Microsoft\Silverlight\v3.0\Microsoft.Silverlight.Common.targets(210,9):
error MSB4018: The "ValidateXaml" task failed unexpectedly.
C:\Program Files\MSBuild\Microsoft\Silverlight\v3.0\Microsoft.Silverlight.Common.targets(210,9):
error MSB4018: System.IO.FileLoadException: Could not load file
or assembly 'file:///u:\Projects\HelloSilverlight3\HelloSilverlight3\obj\Debug\HelloSilverlight3.dll'
or one of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515)$0
C:\Program Files\MSBuild\Microsoft\Silverlight\v3.0\Microsoft.Silverlight.Common.targets(210,9):
error MSB4018:
File name: 'file:///u:\Projects\HelloSilverlight3\HelloSilverlight3\obj\Debug\HelloSilverlight3.dll'
---> System.NotSupportedException: An attempt was made to load an assembly from a network location
which would have caused the assembly to be sandboxed in previous versions of the .NET Framework.
This release of the .NET Framework does not enable CAS policy by default$0 $0, so this load may be dangerous.
If this load is not intended to sandbox the assembly
, please enable the loadFromRemoteSources switch.
See http://go.microsoft.com/fwlink/?LinkId=155569 for more information.