diff --git a/PROMS/VEPROMS User Interface/frmSectionProperties.cs b/PROMS/VEPROMS User Interface/frmSectionProperties.cs
index 7e550cda..18d658b5 100644
--- a/PROMS/VEPROMS User Interface/frmSectionProperties.cs	
+++ b/PROMS/VEPROMS User Interface/frmSectionProperties.cs	
@@ -122,8 +122,9 @@ namespace VEPROMS
 			CheckOffHeaderList chkoffHeaderList = pf.FormatData.ProcData.CheckOffData.CheckOffHeaderList;
 			int maxindx = pf.FormatData.ProcData.CheckOffUCF ? pf.FormatData.ProcData.CheckOffData.CheckOffList.MaxIndex : pf.FormatData.ProcData.CheckOffData.CheckOffList.MaxIndexNoInherit;
 			// C2020-003 use the _CheckOffIndex dictionary to get and save the index of the selected checkoff from the sorted checkoff list
+			// B2020-039: Added the check for a valid selected index so that crash doesn't occur
 			if (ppGpbxSignoffCheckoff.Enabled && (chkoffList != null && maxindx > 1)
-				&& (_CheckOffIndex[ppCmbxCheckoffType.SelectedIndex] != _SectionConfig.Section_CheckoffListSelection))
+				&& (ppCmbxCheckoffType.SelectedIndex > -1 && _CheckOffIndex[ppCmbxCheckoffType.SelectedIndex] != _SectionConfig.Section_CheckoffListSelection))
 				_SectionConfig.Section_CheckoffListSelection = _CheckOffIndex[ppCmbxCheckoffType.SelectedIndex];
 			if (ppCmbxCheckoffHeading.Enabled && chkoffHeaderList != null && chkoffHeaderList.MaxIndexNoInherit > 1)
 				_SectionConfig.Section_CheckoffHeaderSelection = ppCmbxCheckoffHeading.SelectedIndex;