diff --git a/tools/task_plots/plot_tasks.py b/tools/task_plots/plot_tasks.py
index 6458b238bfef9e7a305ec351e2d61ee0a10780d2..a0d58e35134804fcee9288ce6075b293894deb66 100755
--- a/tools/task_plots/plot_tasks.py
+++ b/tools/task_plots/plot_tasks.py
@@ -412,7 +412,7 @@ sdata = sdata[sdata[:, toccol] != 0]
 
 if delta_t < 0.:
     print("The time-range must be >=0!")
-    return 1
+    sys.exit(1)
 # Each rank can have different clocks (compute node), but we want to use the
 # same delta times range for comparisons, so we suck it up and take the hit of
 # precalculating this, unless the user knows better.