diff --git a/rowers/interactiveplots.py b/rowers/interactiveplots.py
index 8f8715e1..25a181c2 100644
--- a/rowers/interactiveplots.py
+++ b/rowers/interactiveplots.py
@@ -236,7 +236,10 @@ def interactive_activitychart(workouts,startdate,enddate,stack='type'):
             dates.append(dd)
             durations.append(du)
             types.append(w.workouttype)
-            rowers.append(w.user.user.first_name[0]+w.user.user.last_name[0])
+            try:
+                rowers.append(w.user.user.first_name[0]+w.user.user.last_name[0])
+            except IndexError:
+                rowers.append(str(w.user))
 
     try:
         d = utc.localize(startdate)