We apply Freeman's variant of the Davenport-Heilbronn method to investigate the exceptional set of real numbers not close to some value of a given real diagonal form at an integral argument. Under appropriate conditions, we show that the exceptional set in the interval [−N, N ] has measure O(N 1−δ ), for a positive number δ.It therefore follows by subtracting (5.1) that22 SCOTT T. PARSELL AND TREVOR D. WOOLEY where the summations are over subsets J of {1, . . . , s + 1}, and whereApplying the analysis leading to [46, Lemma 6.1], as in the argument following Brüdern and Wooley [15, equation (6.6)], we find that whenever s k, one hasAs in the proof of Theorem 1.4 from §3, with * equal to + or −, we denote by Z * J the set of µ ∈ Z for which (5.2) holds with R µ J = R * J , and we write Z * J = meas(Z * J ). It follows that for some choices of * and J, one has Z 2 s+2 Z * J . We fix these choices of * and J henceforth. For each µ ∈ Z * J , we then determine the complex number η µ of modulus 1 by means of the relation |R * J (µ; m ∪ t)| = η µ R * J (µ; m ∪ t). Integrating (5.2) over Z * J gives the upper bound P s+1−k ψ(N) −1 Z ≪ m∪t i∈J