Fix for Silverlight 4 and Windows Phone Developer Tools CTP issues

Microsoft reprts that "the latest update of Silverlight 4 (the 'GDR0 of SL4') which hit Microsoft Update last Thursday can cause Windows Phone Developer Tools CTP – April Refresh to fail to install. If this SL4 update has been installed and you try to install the tools CTP Refresh the installation will fail while attempting […]

Microsoft reprts that "the latest update of Silverlight 4 (the 'GDR0 of SL4') which hit Microsoft Update last Thursday can cause Windows Phone Developer Tools CTP – April Refresh to fail to install. If this SL4 update has been installed and you try to install the tools CTP Refresh the installation will fail while attempting to install Silverlight 4," said Microsoft.

If you run into this while trying to install WPDT CTP Refresh, you can solve it by doing following: Go to the Programs and Feature control panel; Locate the item named Microsoft Silverlight 4 and uninstall it; Re-run the Windows Phone Developer Tools setup.

This issue will be addressed in a future release of the Windows Phone Developer Tools.

[Source]