diff --git a/rowers/dataprep.py b/rowers/dataprep.py
index 94c6f1f5..6110cf26 100644
--- a/rowers/dataprep.py
+++ b/rowers/dataprep.py
@@ -1941,7 +1941,10 @@ def dataprep(rowdatadf, id=0, bands=True, barchart=True, otwpower=True,
 
     f = rowdatadf['TimeStamp (sec)'].diff().mean()
     if f != 0 and not np.isinf(f):
-        windowsize = 2 * (int(10. / (f))) + 1
+        try:
+            windowsize = 2 * (int(10. / (f))) + 1
+        except ValueError:
+            windowsize = 1
     else:
         windowsize = 1
     if windowsize <= 3: