I can confirm an error aswell when trying to slipstream SP1 RC1 (Wave1). It just aborts in the middle of the "Preparing" process (around 16-17%, just when "integrating seems to start") RT Seven Lite used: 2.4.0 Beta Host OS used: Win7 Home Premium 64Bit German (RT7Lited version) OS to be 7lited: Win7 Home Premium 64 Bit German