diff --git a/atdb/taskdatabase/models.py b/atdb/taskdatabase/models.py
index 24ebb6e20ff3de5b601b2124be8e4bc4e0303a2e..5f6e51cc8b849143fe3e65ab5b98c4b3e65160b4 100644
--- a/atdb/taskdatabase/models.py
+++ b/atdb/taskdatabase/models.py
@@ -149,11 +149,15 @@ def check_if_summary(task):
     for backward compatiblity reasons this is done very ugly, by looking if certain filenames contain the substring 'summary'
     """
     # look in the outputs.tar_archive
-    tars = task.outputs['tar_archive']
-    for tar in tars:
-        if 'summary' in tar['basename']:
-            # a summary tarball was found, this task is a summary task
-            return True
+    try:
+        tars = task.outputs['tar_archive']
+        for tar in tars:
+            if 'summary' in tar['basename']:
+                # a summary tarball was found, this task is a summary task
+                return True
+    except:
+        # no 'tar_archive' was found
+        return False
 
     return False