diff --git a/src/clj/auto_ap/datomic/transactions.clj b/src/clj/auto_ap/datomic/transactions.clj
index 11adc67a..1ef89814 100644
--- a/src/clj/auto_ap/datomic/transactions.clj
+++ b/src/clj/auto_ap/datomic/transactions.clj
@@ -206,6 +206,11 @@
                      (map #(assoc % :transaction/is-locked (is-locked? %)))
                      (map #(update % :transaction/date coerce/from-date))
                      (map #(update % :transaction/post-date coerce/from-date))
+                     (map (fn [t]
+                            (let [cn (:transaction/check-number t)]
+                              (if (and cn (nat-int? cn) (> cn Integer/MAX_VALUE))
+                                (dissoc t :transaction/check-number)
+                                t))))
                      (map #(update % :transaction/accounts
                                    (fn [tas]
                                      (map