diff --git a/cfs-autoform-hooks.js b/cfs-autoform-hooks.js
index ac3c5d8..b95ac53 100644
--- a/cfs-autoform-hooks.js
+++ b/cfs-autoform-hooks.js
@@ -225,7 +225,7 @@ Hooks = {
       // or push it into the array of IDs if it's a multiple files field.
       else {
         if (arrayFields[key]) {
-          CfsAutoForm.Util.deepFind(doc.$set,key).push(fileObj._id);
+          CfsAutoForm.Util.deepFind(doc.$set,key)[key].push(fileObj._id);
         } else {
           //doc[key] = fileObj._id;
           CfsAutoForm.Util.deepSet(doc.$set,key,fileObj._id);