diff --git a/chrome/content/zotero/elements/attachmentBox.js b/chrome/content/zotero/elements/attachmentBox.js
index d0ae7b90ce..ba5aa85f48 100644
--- a/chrome/content/zotero/elements/attachmentBox.js
+++ b/chrome/content/zotero/elements/attachmentBox.js
@@ -561,7 +561,7 @@
 				return "";
 			};
 			newFilename = newFilename.trim();
-			let oldFilename = item.getFilename();
+			let oldFilename = item.attachmentFilename;
 			if (oldFilename === newFilename) {
 				return;
 			}