This chapter analyses the careers of two distinct narratives about Mach’s philosophical legacy that prevailed among German-speaking physicists and philosophers for more than a generation. Planck’s polemic against Mach sired the idea of a Machian philosophical system that was irreconcilable with modern physics, Boltzmann’s legacy foremost. But Planck also bereaved Mach’s positivism of its naturalist foundation and identified it straight with phenomenalism. In contrast, many Austrians considered the epistemologies of Mach and Boltzmann as even mutually supportive for a defence of empiricist indeterminism. Taking positivism in its original, more general understanding, they underscored Mach’s broader anti-metaphysical and empiricist stance, eventually adopting him as a standard-bearer for the new movement of Logical Empiricism. While these understandings were not necessarily tied to a positive or negative assessment, they often amounted to simplifications, transformations, or even contortions of Mach’s thinking, which made it increasingly difficult to declare oneself in Mach’s footsteps and simultaneously to advocate scientific modernism.