diff --git a/apps/buffering.c b/apps/buffering.c
index 451fa661ee..5fda50198f 100644
--- a/apps/buffering.c
+++ b/apps/buffering.c
@@ -685,7 +685,7 @@ static bool buffer_handle(int handle_id)
             /* stop buffering data for now and post-pone buffering the rest */
             stop = true;
             DEBUGF( "%s(): Preventing handle corruption: h1.id:%d h2.id:%d"
-                    " copy_n:%zu overlap:%ld h1.filerem:%lu\n", __func__,
+                    " copy_n:%lu overlap:%zd h1.filerem:%lu\n", __func__,
                     h->id, h->next->id, (unsigned long)copy_n, overlap,
                     (unsigned long)h->filerem);
             copy_n -= overlap;