diff --git a/tools/migration/nighthike/6.js b/tools/migration/nighthike/6.js
index ff78df4e0..8b97e9f7b 100644
--- a/tools/migration/nighthike/6.js
+++ b/tools/migration/nighthike/6.js
@@ -1 +1,13 @@
-db.posts.update({ mediaIds: null }, { $set: { mediaIds: [] } }, false, true);
+db.posts.update({
+	$or: [{
+		mediaIds: null
+	}, {
+		mediaIds: {
+			$exist: false
+		}
+	}]
+}, {
+	$set: {
+		mediaIds: []
+	}
+}, false, true);