This paper describes a study aimed to identify commonly emerging impediments related to the introduction of dynamic mathematics software. We report on the analysis of data collected during a three-week professional development programme organised for middle and high school teachers in Florida. The study identified challenges that participants face during software introductory workshops and evaluated the difficulty levels of the dynamic geometry tools and other features used. Based on the data analysis, complexity criteria for dynamic geometry software tools were developed and commonly occurring difficulties were identified, which provided the basis for the development of several new introductory materials and pedagogy that could assist workshop activities and contribute to the improvement of future introductory professional development workshops with dynamic mathematics software. (Contains 1 table and 1 figure.)