[CONNECT SDK] .NET Framework version

Installed CONNECT Update 4 and the SDK.  I rebuilt all the SDK examples.  The C++ examples build OK, but the .NET examples advise me that "warning MSB3644: The reference assemblies for framework ".NETFramework,Version=v4.5.
2" were not found. To resolve this, install the SDK or Targeting Pack for this framework version
 or retarget your application to a version of the framework for which you have the SDK or Target
ing Pack installed"

I updated .NET Framework.  Then I opened a .NET project in Viz Studio, chose Properties and selected a new Target framework for the project.  That pops an error dialog with this message:

TargetFrameworkMoniker:

The expression "[System.IO.Path]::Combine(G:\Program Files\Bentley\MicroStation CONNECT Edition\SDK\examples\Annotations\DescribeElementExample,

      G:\PROGRA~1\Bentley\MICROS~2\MICROS~1\mdlapps\

    )" cannot be evaluated. Illegal characters in path.  C:\Program Files (x86)\MSBuild\12.0\bin\Microsoft.Common.CurrentVersion.targets

I have no idea what causes that error.