diff --git a/db/version_set.cc b/db/version_set.cc
index b68923bc0..507a018bb 100644
--- a/db/version_set.cc
+++ b/db/version_set.cc
@@ -1472,7 +1472,7 @@ class VersionSet::Builder {
         }
       }
       if (!found) {
-        fprintf(stderr, "not found %ld\n", number);
+        fprintf(stderr, "not found %" PRIu64 "\n", number);
       }
       assert(found);
 #endif