Recent advancements in duplex stainless steels (DSS) and wire-based additive manufacturing (AM) have revealed a higher susceptibility to solidification cracking than previously reported. This vulnerability is associated with straight columnar ferrite grain boundaries and the presence of low-melting phases triggered by impurities. Solidification cracks were investigated after being observed in laser beam directed energy deposition with wire (DED-LB/w) of AM 2205 type, and in electron beam welding (EBW) of lean duplex UNS S32101, where a nickel-based wire of ERNiCrMo-13 type was used to promote austenite formation. In DED-LB/w builds, cracking was associated with irregularities such as partially molten wire, lack-of-fusion, and porosity. Susceptibility correlated with the presence of coarse ferrite grains and a limited amount of allotriomorphic austenite. All cracks were located in center beads, where grain boundary austenite was insufficient to accommodate otherwise typical impurity levels under the prevailing residual stresses. The crack surfaces exhibited relatively flat primary dendrites, a feature characteristic of DSS. However, crack initiation required the presence of some form of defect resulting from process instability. In contrast, the crack observed in EBW displayed secondary dendrite arms. While initiation appeared to stem from low-melting phases, tensile stresses promoted crack propagation by separating interdendritic liquid films.