diff --git a/chrome/content/zotero/zoteroPane.js b/chrome/content/zotero/zoteroPane.js
index b44ceeb9f1..fc613172d6 100644
--- a/chrome/content/zotero/zoteroPane.js
+++ b/chrome/content/zotero/zoteroPane.js
@@ -5683,7 +5683,7 @@ var ZoteroPane = new function()
 			var newName = Zotero.Attachments.getFileBaseNameFromItem(parentItem);
 			
 			let extRE = /\.[^\.]+$/;
-			let origFilename = file.split("/").pop();
+			let origFilename = PathUtils.split(file).pop();
 			let ext = origFilename.match(extRE);
 			if (ext) {
 				newName = newName + ext[0];