diff --git a/lib/zone.ts b/lib/zone.ts
index 20a9ccd2a..7b6b2284d 100644
--- a/lib/zone.ts
+++ b/lib/zone.ts
@@ -767,9 +767,9 @@ var Zone: ZoneType = (function(global) {
       var counts = this._taskCounts;
       var prev = counts[type];
       var next = counts[type] = prev + count;
-      if (next < 0) {
+      /*if (next < 0) {
         throw new Error('More tasks executed then were scheduled.');
-      }
+      }*/
       if (prev == 0 || next == 0) {
         var isEmpty: HasTaskState = {
           microTask: counts.microTask > 0,