The effect of the parameters of selective laser melting (SLM) on the formation of cracks in a monocrystalline nickel heat-resistant alloy with preheating of the substrate to 1200 °C. It was found that an increase in linear and volumetric energy density suppresses cracking, reducing the number of defects, and it is also shown that cracks originate mainly along the boundaries of dendrites in the zones of segregation of alloying elements and the release of carbides Ta and Mo. It is concluded that increasing the energy parameters of SLM reduces the rate of crystallization, ensures more uniform solidification and contributes to a significant reduction in the number of cracks.