diff --git a/lib/formats/villas_human.c b/lib/formats/villas_human.c
index 4c4fb6b07..b969d1527 100644
--- a/lib/formats/villas_human.c
+++ b/lib/formats/villas_human.c
@@ -227,7 +227,7 @@ void villas_human_header(struct io *io, const struct sample *smp)
 		fprintf(f, "(sequence)");
 
 	if (io->flags & SAMPLE_HAS_DATA) {
-		for (int i = 0; i < smp->length; i++) {
+		for (int i = 0; i < MIN(smp->length, vlist_length(smp->signals)); i++) {
 			struct signal *sig = (struct signal *) vlist_at(smp->signals, i);
 
 			if (sig->name)