Spiro-thiazolones of formula I wherein X1, X2, X3, X4, R2, R3, R4, R5, R6 and R7 are as defined herein, which act as V1a receptor modulators, and in particular as V1a receptor antagonists, their manufacture, pharmaceutical compositions containing them and their use as medicaments for treatment of inappropriate secretion of vasopressin, anxiety, depressive disorders, obsessive compulsive disorder, autistic spectrum disorders, schizophrenia, aggressive behavior and phase shift sleep disorders, in particular jetlag.