diff --git a/src/HtmlAgilityPack.Shared/HtmlNode.cs b/src/HtmlAgilityPack.Shared/HtmlNode.cs
index 9927f1c..69f2529 100644
--- a/src/HtmlAgilityPack.Shared/HtmlNode.cs
+++ b/src/HtmlAgilityPack.Shared/HtmlNode.cs
@@ -2011,20 +2011,23 @@ internal void UpdateLastNode()
 			HtmlNode newLast = null;
 			if (_prevwithsamename == null || !_prevwithsamename._starttag)
 			{
-				foreach (var openNode in _ownerdocument.Openednodes)
-				{
-					if ((openNode.Key < _outerstartindex || openNode.Key > (_outerstartindex + _outerlength)) && openNode.Value._name == _name)
-					{
-						if (newLast == null && openNode.Value._starttag)
-						{
-							newLast = openNode.Value;
-						}
-						else if (newLast !=null && newLast.InnerStartIndex < openNode.Key && openNode.Value._starttag)
-						{
-							newLast = openNode.Value;
-						}
-					}
-				}
+                if (_ownerdocument.Openednodes != null)
+                {
+                    foreach (var openNode in _ownerdocument.Openednodes)
+                    {
+                        if ((openNode.Key < _outerstartindex || openNode.Key > (_outerstartindex + _outerlength)) && openNode.Value._name == _name)
+                        {
+                            if (newLast == null && openNode.Value._starttag)
+                            {
+                                newLast = openNode.Value;
+                            }
+                            else if (newLast != null && newLast.InnerStartIndex < openNode.Key && openNode.Value._starttag)
+                            {
+                                newLast = openNode.Value;
+                            }
+                        }
+                    }
+                }
 			}
 			else
 			{
diff --git a/src/Tests/HtmlAgilityPack.Tests.Net45/HtmlDocumentTests.cs b/src/Tests/HtmlAgilityPack.Tests.Net45/HtmlDocumentTests.cs
index 6adb6ef..ec08cb5 100644
--- a/src/Tests/HtmlAgilityPack.Tests.Net45/HtmlDocumentTests.cs
+++ b/src/Tests/HtmlAgilityPack.Tests.Net45/HtmlDocumentTests.cs
@@ -1206,6 +1206,27 @@ public void AttributeSerialization()
 
         }
 
+        [Test]
+        public void LoadHtml_WhenHtmlHasUnclosedTags_AndOptionCheckSyntaxFalse_ShouldNotThrowException()
+        {
+            var html = "<div>Some simple <p> html</div>";
+            var htmlDoc = new HtmlDocument { OptionCheckSyntax = false };
+
+            htmlDoc.LoadHtml(html);
+
+            using (var memoryStream = new MemoryStream())
+            {
+                htmlDoc.Save(memoryStream);
+                memoryStream.Seek(0, SeekOrigin.Begin);
+                using (var streamReader = new StreamReader(memoryStream))
+                {
+                    string parsedHtml = streamReader.ReadToEnd();
+                    Assert.IsNotEmpty(parsedHtml);
+                }
+            }
+            Assert.Zero(htmlDoc.ParseErrors.Count());
+        }
+
         [HasXPath]
         public class StackOverflowPage
         {