diff --git a/lib/formats/csv.c b/lib/formats/csv.c
index 3e5eca362..4ce3b779a 100644
--- a/lib/formats/csv.c
+++ b/lib/formats/csv.c
@@ -46,7 +46,7 @@ static size_t csv_sprint_single(struct io *io, char *buf, size_t len, struct sam
 		off += snprintf(buf + off, len - off, "%cnan", io->separator);
 
 	if (io->flags & SAMPLE_HAS_SEQUENCE)
-		off += snprintf(buf + off, len - off, "%c%lu", io->separator, s->sequence);
+		off += snprintf(buf + off, len - off, "%c%llu", io->separator, s->sequence);
 	else
 		off += snprintf(buf + off, len - off, "%cnan", io->separator);
 
diff --git a/lib/formats/villas_human.c b/lib/formats/villas_human.c
index a23faebbf..214a6b9e3 100644
--- a/lib/formats/villas_human.c
+++ b/lib/formats/villas_human.c
@@ -45,7 +45,7 @@ static size_t villas_human_sprint_single(struct io *io, char *buf, size_t len, s
 		off += snprintf(buf + off, len - off, "%+e", time_delta(&s->ts.origin, &s->ts.received));
 
 	if (io->flags & SAMPLE_HAS_SEQUENCE)
-		off += snprintf(buf + off, len - off, "(%lu)", s->sequence);
+		off += snprintf(buf + off, len - off, "(%llu)", s->sequence);
 
 	if (io->flags & SAMPLE_HAS_VALUES) {
 		for (int i = 0; i < s->length; i++) {
diff --git a/lib/hooks/drop.c b/lib/hooks/drop.c
index 5193d0363..5653f1188 100644
--- a/lib/hooks/drop.c
+++ b/lib/hooks/drop.c
@@ -68,7 +68,7 @@ static int drop_read(struct hook *h, struct sample *smps[], unsigned *cnt)
 			if (dist <= 0) {
 				cur->flags |= SAMPLE_IS_REORDERED;
 
-				debug(10, "Dropping reordered sample: sequence=%lu, distance=%d", cur->sequence, dist);
+				debug(10, "Dropping reordered sample: sequence=%llu, distance=%d", cur->sequence, dist);
 			}
 			else
 				goto ok;
diff --git a/lib/hooks/restart.c b/lib/hooks/restart.c
index edc2b09f1..9ee484564 100644
--- a/lib/hooks/restart.c
+++ b/lib/hooks/restart.c
@@ -66,7 +66,7 @@ static int restart_read(struct hook *h, struct sample *smps[], unsigned *cnt)
 		if (prev) {
 			/* A wrap around of the sequence no should not be treated as a simulation restart */
 			if (cur->sequence == 0 && prev->sequence <= (int) (UINT32_MAX - 128)) {
-				warn("Simulation from node %s restarted (previous->seq=%lu, current->seq=%lu)",
+				warn("Simulation from node %s restarted (previous->seq=%llu, current->seq=%llu)",
 					node_name(h->node), prev->sequence, cur->sequence);
 
 				cur->flags |= SAMPLE_IS_FIRST;
diff --git a/lib/sample.c b/lib/sample.c
index 573a6abb5..6e9211ac3 100644
--- a/lib/sample.c
+++ b/lib/sample.c
@@ -215,7 +215,7 @@ int sample_cmp(struct sample *a, struct sample *b, double epsilon, int flags)
 	/* Compare sequence no */
 	if (flags & SAMPLE_HAS_SEQUENCE) {
 		if (a->sequence != b->sequence) {
-			printf("sequence no: %ld != %ld\n", a->sequence, b->sequence);
+			printf("sequence no: %lld != %lld\n", a->sequence, b->sequence);
 			return 2;
 		}
 	}
diff --git a/src/villas-test-rtt.cpp b/src/villas-test-rtt.cpp
index 8b86474ec..e4c1bbfd8 100644
--- a/src/villas-test-rtt.cpp
+++ b/src/villas-test-rtt.cpp
@@ -185,7 +185,7 @@ void test_rtt() {
 
 		smp_send->sequence++;
 
-		fprintf(stdout, "%10lu.%06lu%5lu%10.3f%10.3f%10.3f%10.3f%10.3f\n",
+		fprintf(stdout, "%10lu.%06lu%5llu%10.3f%10.3f%10.3f%10.3f%10.3f\n",
 			recv.tv_sec, recv.tv_nsec / 1000, smp_send->sequence,
 			1e3 * rtt, 1e3 * hist.lowest, 1e3 * hist.highest,
 			1e3 * hist_mean(&hist), 1e3 * hist_stddev(&hist));