diff --git a/serial.cpp b/serial.cpp
index 6d13b8c..c3b6649 100644
--- a/serial.cpp
+++ b/serial.cpp
@@ -212,7 +212,9 @@ void serialize_feature(FILE *geomfile, serial_feature *sf, long long *geompos, c
 	}
 
 	serialize_int(geomfile, sf->m, geompos, fname);
-	serialize_long_long(geomfile, sf->metapos, geompos, fname);
+	if (sf->m != 0) {
+		serialize_long_long(geomfile, sf->metapos, geompos, fname);
+	}
 
 	if (sf->metapos < 0 && sf->m != sf->keys.size()) {
 		fprintf(stderr, "Internal error: %lld doesn't match %lld\n", (long long) sf->m, (long long) sf->keys.size());
diff --git a/tile.cpp b/tile.cpp
index fcd2ead..3b782d0 100644
--- a/tile.cpp
+++ b/tile.cpp
@@ -1337,10 +1337,12 @@ long long write_tile(FILE *geoms, long long *geompos_in, char *metabase, char *s
 				deserialize_long_long_io(geoms, &extent, geompos_in);
 			}
 
-			long long metastart;
+			long long metastart = 0;
 			int m;
 			deserialize_int_io(geoms, &m, geompos_in);
-			deserialize_long_long_io(geoms, &metastart, geompos_in);
+			if (m != 0) {
+				deserialize_long_long_io(geoms, &metastart, geompos_in);
+			}
 			char *meta = NULL;
 			std::vector<long long> metakeys, metavals;