diff --git a/astrid/plugin-src/com/todoroo/astrid/gtasks/GtasksListService.java b/astrid/plugin-src/com/todoroo/astrid/gtasks/GtasksListService.java
index 8bd2100a4..18958c2f9 100644
--- a/astrid/plugin-src/com/todoroo/astrid/gtasks/GtasksListService.java
+++ b/astrid/plugin-src/com/todoroo/astrid/gtasks/GtasksListService.java
@@ -77,7 +77,7 @@ public class GtasksListService {
     }
 
     @SuppressWarnings("nls")
-    public void updateLists(TaskLists remoteLists) {
+    public synchronized void updateLists(TaskLists remoteLists) {
         readLists();
 
         for(StoreObject list : lists)