diff --git a/app/src/main/java/info/nightscout/androidaps/plugins/general/overview/graphExtensions/TimeAsXAxisLabelFormatter.java b/app/src/main/java/info/nightscout/androidaps/plugins/general/overview/graphExtensions/TimeAsXAxisLabelFormatter.java
index c5e5441470..18feddf916 100644
--- a/app/src/main/java/info/nightscout/androidaps/plugins/general/overview/graphExtensions/TimeAsXAxisLabelFormatter.java
+++ b/app/src/main/java/info/nightscout/androidaps/plugins/general/overview/graphExtensions/TimeAsXAxisLabelFormatter.java
@@ -4,6 +4,7 @@ import com.jjoe64.graphview.DefaultLabelFormatter;
 
 import java.text.DateFormat;
 import java.text.SimpleDateFormat;
+import java.util.Locale;
 
 /**
  * Created by mike on 09.06.2016.
@@ -20,10 +21,22 @@ public class TimeAsXAxisLabelFormatter extends DefaultLabelFormatter {
     public String formatLabel(double value, boolean isValueX) {
         if (isValueX) {
             // format as date
-            DateFormat dateFormat = new SimpleDateFormat(mFormat);
+            DateFormat dateFormat = new SimpleDateFormat(mFormat, Locale.getDefault());
             return dateFormat.format((long) value);
         } else {
-            return super.formatLabel(value, isValueX);
+            try {
+                // unknown reason for crashing on this
+                //                Fatal Exception: java.lang.NullPointerException
+                //                Attempt to invoke virtual method 'double com.jjoe64.graphview.Viewport.getMaxY(boolean)' on a null object reference
+                //                com.jjoe64.graphview.DefaultLabelFormatter.formatLabel (DefaultLabelFormatter.java:89)
+                //                info.nightscout.androidaps.plugins.general.overview.graphExtensions.TimeAsXAxisLabelFormatter.formatLabel (TimeAsXAxisLabelFormatter.java:26)
+                //                com.jjoe64.graphview.GridLabelRenderer.drawVerticalSteps (GridLabelRenderer.java:1057)
+                //                com.jjoe64.graphview.GridLabelRenderer.draw (GridLabelRenderer.java:866)
+                //                com.jjoe64.graphview.GraphView.onDraw (GraphView.java:296)
+                return super.formatLabel(value, isValueX);
+            } catch (Exception ignored) {
+                return "";
+            }
         }
     }
 }