Install problem with the Developer Tools CTP Refresh

We have discovered that the latest update of Silverlight 4 (the “GDR0 of SL4”) which hit Microsoft Update last Thursday can cause the 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.

If you run into this while trying to install the WPDT CTP Refresh, you can solve it by doing the following:

1. Go to the Programs and Feature control panel.
2. Locate the item named Microsoft Silverlight 4 and uninstall it.
3. Re-run the Windows Phone Developer Tools setup.

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