diff --git a/web/static/js/swapp.js b/web/static/js/swapp.js
index 86a2daa..70e722f 100644
--- a/web/static/js/swapp.js
+++ b/web/static/js/swapp.js
@@ -112,6 +112,9 @@
           configuration['parameters'].forEach(function(parameter){
             return data[parameter['id']] = [];
           });
+          if (!csv) {
+            reject("CSV is empty or nonexistent at URL '" + url + "'.");
+          }
           csv.forEach(function(d){
             var dtime;
             dtime = timeFormat(d['time']);
--
libgit2 0.21.2