diff --git a/PROMS/VEPROMS User Interface/frmSectionProperties.cs b/PROMS/VEPROMS User Interface/frmSectionProperties.cs
index 3493c02a..edc95e84 100644
--- a/PROMS/VEPROMS User Interface/frmSectionProperties.cs	
+++ b/PROMS/VEPROMS User Interface/frmSectionProperties.cs	
@@ -721,16 +721,19 @@ namespace VEPROMS
 				return;
 			}
 			if (_InitialIndex < -1) _InitialIndex = ppCmbxFormat.SelectedIndex; // save the current format selection (happens here when current section format is not the default section)
-			PlantFormat pf = FormatInfoList.SortedFormatInfoList[ppCmbxFormat.SelectedIndex].PlantFormat;
-			// If the selected format does not have a docstyle compatable with the section
-			// then reset the format selection back to what it was
-			if (!ValidPlantFormat(pf))
+			if (ppCmbxFormat.SelectedIndex > -1)  // B2017-016 selectedindex of -1 means the default format was selected
 			{
-				_Initializing = true;
-				ppCmbxFormat.SelectedIndex = _InitialIndex; // reset the format selection to what it was
-				ppBtnCancel.Focus(); // this will force the property page to refresh
-				_Initializing = false;
-				return;
+				PlantFormat pf = FormatInfoList.SortedFormatInfoList[ppCmbxFormat.SelectedIndex].PlantFormat;
+				// If the selected format does not have a docstyle compatable with the section
+				// then reset the format selection back to what it was
+				if (!ValidPlantFormat(pf))
+				{
+					_Initializing = true;
+					ppCmbxFormat.SelectedIndex = _InitialIndex; // reset the format selection to what it was
+					ppBtnCancel.Focus(); // this will force the property page to refresh
+					_Initializing = false;
+					return;
+				}
 			}
 			if ((ppCmbxFormat.SelectedIndex != -1) && _DefaultFormatName != null && _DefaultFormatName.Equals(ppCmbxFormat.SelectedValue))
 			{