diff --git a/ntfsprogs/mkntfs.c b/ntfsprogs/mkntfs.c
index 14c66ccf..e6a412c4 100644
--- a/ntfsprogs/mkntfs.c
+++ b/ntfsprogs/mkntfs.c
@@ -4284,7 +4284,8 @@ static void mkntfs_create_root_structures(void)
 	ATTR_RECORD *a;
 	MFT_RECORD *m;
 	MFT_REF root_ref, extend_ref;
-	int i, j, err, mft_total_cluster_size;
+	int i, j, err;
+	unsigned mft_total_cluster_size;
 	u8 *sd;
 	FILE_ATTR_FLAGS extend_flags;
 	VOLUME_FLAGS volume_flags = 0;