diff --git a/chrome/content/zotero/zoteroPane.js b/chrome/content/zotero/zoteroPane.js
index 5bdd8f36ac..99e1deacad 100644
--- a/chrome/content/zotero/zoteroPane.js
+++ b/chrome/content/zotero/zoteroPane.js
@@ -387,16 +387,22 @@ var ZoteroPane = new function()
 		Zotero.debug("Purged data tables in " + (d2 - d) + " ms");
 		
 		// Auto-sync on pane open
-		if (Zotero.Prefs.get('sync.autoSync') && Zotero.Sync.Server.enabled
-				&& !Zotero.Sync.Server.syncInProgress && !Zotero.Sync.Storage.syncInProgress) {
-			if (Zotero.Sync.Server.manualSyncRequired) {
-				Zotero.debug('Manual sync required -- skipping auto-sync', 4);
-			}
-			else {
-				setTimeout(function () {
-					Zotero.Sync.Runner.sync(true);
-				}, 1000);
-			}
+		if (Zotero.Prefs.get('sync.autoSync')) {
+			setTimeout(function () {
+				if (!Zotero.Sync.Server.enabled
+						|| Zotero.Sync.Server.syncInProgress
+						|| Zotero.Sync.Storage.syncInProgress) {
+					Zotero.debug('Sync already running -- skipping auto-sync', 4);
+					return;
+				}
+				
+				if (Zotero.Sync.Server.manualSyncRequired) {
+					Zotero.debug('Manual sync required -- skipping auto-sync', 4);
+					return;
+				}
+				
+				Zotero.Sync.Runner.sync(true);
+			}, 1000);
 		}
 		
 		return true;