diff --git a/contrib/testRender.py b/contrib/testRender.py
index 4fa9e7e..a928b58 100644
--- a/contrib/testRender.py
+++ b/contrib/testRender.py
@@ -51,7 +51,10 @@ def clean_render(overviewerargs, quiet):
     try:
         # check_call raises CalledProcessError when overviewer.py exits badly
         check_call(['python', 'setup.py', 'clean', 'build'], quiet=quiet)
-        check_call([overviewer_script, '-d'] + overviewerargs, quiet=quiet)
+        try:
+            check_call([overviewer_script, '-d'] + overviewerargs, quiet=quiet)
+        except CalledProcessError:
+            pass
         starttime = time.time()
         check_call([overviewer_script,] + overviewerargs + [tempdir,], quiet=quiet)
         endtime = time.time()