diff --git a/include/class.upgrader.php b/include/class.upgrader.php
index d04b8f2840f61c66f8a03d671700c79e3c715b82..245bfc1504be12165d892fe191105c57f246ec34 100644
--- a/include/class.upgrader.php
+++ b/include/class.upgrader.php
@@ -314,7 +314,7 @@ class StreamUpgrader extends SetupWizard {
     function getPendingTask() {
 
         $pending=array();
-        if (($task=$this->getTask()) && $task)
+        if (($task=$this->getTask()) && ($task instanceof MigrationTask))
             return ($task->isFinished()) ? 1 : 0;
 
         return false;