diff --git a/PROMS/Volian.Controls.Library/DisplayHistory.cs b/PROMS/Volian.Controls.Library/DisplayHistory.cs
index b62345f8..01c415b0 100644
--- a/PROMS/Volian.Controls.Library/DisplayHistory.cs
+++ b/PROMS/Volian.Controls.Library/DisplayHistory.cs
@@ -262,7 +262,8 @@ namespace Volian.Controls.Library
 					if (tn == null)
 					{
 						AnnotationTypeInfo ati = AnnotationTypeInfo.Get(aai.TypeID);
-						tn = annotationDeleted.Nodes.Add(ati.Name);
+						// B2023-066: Crash when trying to access a deleted annotation type (added the ati==null check)
+						tn = annotationDeleted.Nodes.Add(ati==null?"Deleted Annotation Type":ati.Name);
 					}
 					TreeNode cn = tn.Nodes.Add(aai.ListString());
 					cn.Tag = aai;