Earlier today we shipped a public beta of our upcoming .NET 3.5 SP1 and VS 2008 SP1 releases. These servicing updates provide a roll-up of bug fixes and performance improvements for issues reported since we released the products last November. They also contain a number of feature additions and enhancements that make building .NET applications better (see below for details on some of them). We plan to ship the final release of both .NET 3.5 SP1 and VS 2008 SP1 this summer as free updates. You can download and install the beta here . Important: SP1 Beta Installation Notes The SP1 beta released today is still in beta form - so you should be careful about installing it on critical machines. There are a few important SP1 Beta installation notes to be aware of: 1) If you are running Windows Vista you should make sure you have Vista SP1 installed before trying to install .NET 3.5 SP1 Beta. There are some setup issues with .NET 3.5 SP1 when running on the Vista RTM release. These issues will be fixed for the final .NET 3.5 SP1 release - until then please make sure to have Vista SP1 installed before trying to install .NET 3.5 SP1 beta. 2) If you have installed the VS 2008 Tools for Silverlight 2 Beta1 package on your machine, you must uninstall it - as well as uninstall the KB949325 update for VS 2008 - before installing VS 2008 SP1 Beta (otherwise you will get a setup failure). You can find more details ...