First results of the CMS muon system using the 2006 cosmic runs of the magnet test

During summer 2006 the solenoid magnet of CMS was tested for the first time at its nominal field of 4 T with a slice of each sub-detector operational. The first results with the cosmic runs taken in this configuration will be presented here with emphasis on the muon system. The magnet test has provided a unique opportunity to demonstrate the combined operation of CMS components from Magnet, Detector, Control Systems, Trigger, DAQ, Software and computing to allow early identification of problem areas and solutions one year before actual LHC operation starts.