Abstract. Let X be a compact connected strongly pseudoconvex CR manifold of real dimension 2n − 1 in C N . It has been an interesting question to find an intrinsic smoothness criteria for the complex Plateau problem. For n ≥ 3 and N = n + 1, Yau found a necessary and sufficient condition for the interior regularity of the Harvey-Lawson solution to the complex Plateau problem by means of Kohn-Rossi cohomology groups on X in 1981. For n = 2 and N ≥ n + 1, the first and third authors introduced a new CR invariant g (1,1) (X) of X. The vanishing of this invariant will give the interior regularity of the Harvey-Lawson solution up to normalization. For n ≥ 3 and N > n + 1, the problem still remains open. In this paper, we generalize the invariant g (1,1) (X) to higher dimension as g (Λ n 1) (X) and show that if g (Λ n 1) (X) = 0, then the interior has at most finite number of rational singularities. In particular, if X is Calabi-Yau of real dimension 5, then the vanishing of this invariant is equivalent to give the interior regularity up to normalization.