Was missing the catch, if file is missing it returns an exception the UI Demo wasn't catching.

Author: gavin1970

Chizl.FileCompare.csproj

@@ -14,7 +14,7 @@
 				<Company>Chizl.com</Company>
 				<Copyright>© 2025 chizl.com</Copyright>
 				<PackageTags>file-compare;library;in-console;on-desktop;netstandard;core;framework</PackageTags>
-				<FileVersion>5.09.17.26</FileVersion>
+				<FileVersion>5.09.17.126</FileVersion>
 				<Version>5.09.17.0</Version>
 				<AssemblyVersion>5.09.0.0</AssemblyVersion>
 		</PropertyGroup>

Chizl.FileComparer/Properties/AssemblyInfo.cs

@@ -30,7 +30,7 @@
 //      Revision
 //
 [assembly: AssemblyVersion("5.9.0.0")]
-[assembly: AssemblyFileVersion("5.9.17.26")]
+[assembly: AssemblyFileVersion("5.9.17.126")]
 [assembly: AssemblyInformationalVersion("5.9.17.0")]
 [assembly: AssemblyKeyFileAttribute("")]
 [assembly: AssemblyDelaySignAttribute(false)]

Chizl.FileComparer/StartForm.cs

@@ -346,8 +346,13 @@ private void CompareFiles()
                 _lastFileComparison = DiffTool.CompareFiles(this.OldAsciiFile.Text, this.NewAsciiFile.Text, score_threshold, 3);
                 this.ViewAsBinaryButtonToollbar.Visible = !_lastFileComparison.IsBinary;
 
-                ShowComparison(false, _isSideBySide);
-                UpdateHistoryFile();
+                if (_lastFileComparison.HasException)
+                    MessageBox.Show(this, _lastFileComparison.Exception.Message, About.Title, MessageBoxButtons.OK, MessageBoxIcon.Error);
+                else
+                {
+                    ShowComparison(false, _isSideBySide);
+                    UpdateHistoryFile();
+                }
             }
         }
         private void UpdateHistoryFile()