diff --git a/code/FileAttachmentField.php b/code/FileAttachmentField.php
index 60258da..5345908 100644
--- a/code/FileAttachmentField.php
+++ b/code/FileAttachmentField.php
@@ -210,8 +210,8 @@ public function saveInto(DataObjectInterface $record) {
             }
         }
 
-        if(($relation = $this->getRelation()) && is_array($this->Value())) {
-            $relation->setByIDList($this->Value());
+        if(($relation = $this->getRelation())) {
+            $relation->setByIDList((array) $this->Value());
         } elseif($record->has_one($fieldname)) {
             $record->{"{$fieldname}ID"} = $this->Value() ?: 0;
         } elseif($record->hasField($fieldname)) {