While deleterious mutations are responsible for the vast majority of TBK1-linked ALS/FTD cases, the ALS/FTD causing missense mutation p.E696K leads to a selective loss of TBK1/optineurin binding. Knock-in of this specific missense mutation causes progressive autophagolysosomal dysfunction and an ALS/FTD-like phenotype in mice, while, as opposed to TBK1 deletion, RIPK/TNF-α-dependent necroptosis or overt inflammation are absent. Our results highlight the role of autophagolysosomal dysfunction as a therapeutic target in TBK1-ALS/FTD.