Quick Fix: Blend 4 crashing in clr.dll on start after Visual Studio 11 and .NET Framework 4.5 are installed.

This is a live saver. After installing Visual Studio 11 Developer Preview on my x64 Windows 7 machine, Expression Blend 4 and Expression Blend 4 Preview for Silverlight 5 would crash immediately after startup, faulting in “clr.dll”.

The following link saved my setup however:

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 %windir%Microsoft.NETFrameworkv4.0.30319ngen uninstall "%ProgramFiles(x86)%Microsoft ExpressionBlend 4Microsoft.Expression.Framework.dll"
%windir%Microsoft.NETFrameworkv4.0.30319ngen uninstall "%ProgramFiles(x86)%Microsoft ExpressionBlend 4Microsoft.Expression.Blend.dll"
%windir%Microsoft.NETFrameworkv4.0.30319ngen uninstall "%ProgramFiles(x86)%Microsoft ExpressionBlend 4Microsoft.Expression.Project.dll"
 
If "%ProgramFiles(x86)%Microsoft ExpressionBlend 4Microsoft.Expression.WindowsPhone.dll" is present for scenarios like Blend V4 SP1 or future releases, please also run:
%windir%Microsoft.NETFrameworkv4.0.30319ngen uninstall "%ProgramFiles(x86)%Microsoft ExpressionBlend 4Microsoft.Expression.WindowsPhone.dll"

– thanks, ArildF.

Run a Command Prompt with elevated permissions and execute the following lines:

For Expression Blend 4:

%windir%Microsoft.NETFrameworkv4.0.30319ngen uninstall "%ProgramFiles(x86)%Microsoft ExpressionBlend 4Microsoft.Expression.Framework.dll"

%windir%Microsoft.NETFrameworkv4.0.30319ngen uninstall "%ProgramFiles(x86)%Microsoft ExpressionBlend 4Microsoft.Expression.Blend.dll"

%windir%Microsoft.NETFrameworkv4.0.30319ngen uninstall "%ProgramFiles(x86)%Microsoft ExpressionBlend 4Microsoft.Expression.Project.dll"

%windir%Microsoft.NETFrameworkv4.0.30319ngen uninstall "%ProgramFiles(x86)%Microsoft ExpressionBlend 4Microsoft.Expression.WindowsPhone.dll"

For Expression Blend 4 Preview for Silverlight 5

%windir%Microsoft.NETFrameworkv4.0.30319ngen uninstall "%ProgramFiles(x86)%Microsoft ExpressionBlend Preview for Silverlight 5Microsoft.Expression.Framework.dll"

%windir%Microsoft.NETFrameworkv4.0.30319ngen uninstall "%ProgramFiles(x86)%Microsoft ExpressionBlend Preview for Silverlight 5Microsoft.Expression.Blend.dll"

%windir%Microsoft.NETFrameworkv4.0.30319ngen uninstall "%ProgramFiles(x86)%Microsoft ExpressionBlend Preview for Silverlight 5Microsoft.Expression.Project.dll"

%windir%Microsoft.NETFrameworkv4.0.30319ngen uninstall "%ProgramFiles(x86)%Microsoft ExpressionBlend Preview for Silverlight 5Microsoft.Expression.WindowsPhone.dll"

After that, Blend starts and works as expected on my machine.

NOTE: Try at your own risk. At the time of writing, this fix is not officially supported or endorsed by Microsoft.