diff --git a/chrome/content/zotero/xpcom/storage/storageLocal.js b/chrome/content/zotero/xpcom/storage/storageLocal.js
index 992dc1d12..6ed7aba50 100644
--- a/chrome/content/zotero/xpcom/storage/storageLocal.js
+++ b/chrome/content/zotero/xpcom/storage/storageLocal.js
@@ -642,6 +642,7 @@ Zotero.Sync.Storage.Local = {
 			return false;
 		}
 		
+		var dir = OS.Path.dirname(path);
 		var fileName = OS.Path.basename(path);
 		var renamed = false;
 		
@@ -651,7 +652,7 @@ Zotero.Sync.Storage.Local = {
 		if (filteredName != fileName) {
 			Zotero.debug("Filtering filename '" + fileName + "' to '" + filteredName + "'");
 			fileName = filteredName;
-			path = OS.Path.dirname(path, fileName);
+			path = OS.Path.join(dir, fileName);
 			renamed = true;
 		}
 		
@@ -670,7 +671,7 @@ Zotero.Sync.Storage.Local = {
 			Zotero.debug("Changed filename '" + fileName + "' to '" + finalFileName + "'");
 			
 			fileName = finalFileName;
-			path = OS.Path.dirname(path, fileName);
+			path = OS.Path.join(dir, fileName);
 			
 			// Abort if Windows path limitation would cause filenames to be overly truncated
 			if (Zotero.isWin && fileName.length < 40) {
@@ -859,7 +860,7 @@ Zotero.Sync.Storage.Local = {
 					throw new Error(msg);
 				}
 				
-				destPath = OS.Path.join(OS.Path.dirname(destPath, shortened));
+				destPath = OS.Path.join(OS.Path.dirname(destPath), shortened);
 				
 				if (primaryFile) {
 					renamed = true;