Release 1.2.0 reliability improvements

.github/workflows/build-and-release.yml

@@ -102,20 +102,18 @@ jobs:
 
       - name: Create SHA-256 checksum
         shell: pwsh
-        env:
-          APP_VERSION: ${{ steps.version.outputs.number }}
         run: |
-          $installer = Get-Item "artifacts\OneNoteBackupExporter_Setup_$env:APP_VERSION.exe"
+          $installer = Get-Item "artifacts\OneNoteBackupExporter_Setup.exe"
           $hash = (Get-FileHash $installer.FullName -Algorithm SHA256).Hash.ToLowerInvariant()
           "$hash  $($installer.Name)" | Set-Content "$($installer.FullName).sha256" -Encoding ascii
 
       - name: Upload build artifact
         uses: actions/upload-artifact@v4
         with:
-          name: OneNoteBackupExporter-${{ steps.version.outputs.number }}
+          name: OneNoteBackupExporter-Windows-x64
           path: |
-            artifacts/OneNoteBackupExporter_Setup_${{ steps.version.outputs.number }}.exe
-            artifacts/OneNoteBackupExporter_Setup_${{ steps.version.outputs.number }}.exe.sha256
+            artifacts/OneNoteBackupExporter_Setup.exe
+            artifacts/OneNoteBackupExporter_Setup.exe.sha256
           if-no-files-found: error
           retention-days: 14
 
@@ -131,7 +129,7 @@ jobs:
       - name: Download installer artifact
         uses: actions/download-artifact@v4
         with:
-          name: OneNoteBackupExporter-${{ needs.build.outputs.version }}
+          name: OneNoteBackupExporter-Windows-x64
           path: artifacts
 
       - name: Create release and upload installer

AboutWindow.xaml

@@ -0,0 +1,91 @@
+<Window x:Class="OneNoteExporter.AboutWindow"
+        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        Icon="icon.ico"
+        Title="About OneNote Backup Exporter"
+        Width="430" Height="305"
+        ResizeMode="NoResize"
+        ShowInTaskbar="False"
+        WindowStartupLocation="CenterOwner"
+        Background="{StaticResource BgPage}">
+
+    <Border Margin="18"
+            Padding="22"
+            Background="{StaticResource BgCard}"
+            BorderBrush="{StaticResource BorderColor}"
+            BorderThickness="1"
+            CornerRadius="8">
+        <Grid>
+            <Grid.RowDefinitions>
+                <RowDefinition Height="Auto"/>
+                <RowDefinition Height="Auto"/>
+                <RowDefinition Height="*"/>
+                <RowDefinition Height="Auto"/>
+            </Grid.RowDefinitions>
+
+            <Grid Grid.Row="0">
+                <Grid.ColumnDefinitions>
+                    <ColumnDefinition Width="Auto"/>
+                    <ColumnDefinition Width="*"/>
+                </Grid.ColumnDefinitions>
+
+                <Image Grid.Column="0"
+                       Source="icon.ico"
+                       Width="52" Height="52"
+                       Margin="0,0,15,0"/>
+
+                <StackPanel Grid.Column="1" VerticalAlignment="Center">
+                    <TextBlock Text="OneNote Backup Exporter"
+                               FontSize="19"
+                               FontWeight="Bold"
+                               Foreground="{StaticResource PrimaryBlue}"/>
+                    <TextBlock x:Name="VersionText"
+                               Margin="0,4,0,0"
+                               FontSize="13"
+                               FontWeight="SemiBold"
+                               Foreground="{StaticResource TextPrimary}"/>
+                    <TextBlock x:Name="BuildText"
+                               Margin="0,2,0,0"
+                               FontSize="11"
+                               Foreground="{StaticResource TextSecondary}"/>
+                </StackPanel>
+            </Grid>
+
+            <Border Grid.Row="1"
+                    Margin="0,18,0,14"
+                    Padding="12,9"
+                    Background="{StaticResource InfoBg}"
+                    BorderBrush="{StaticResource InfoBorder}"
+                    BorderThickness="1"
+                    CornerRadius="5">
+                <TextBlock Text="Reliable backups and exports for OneNote Desktop."
+                           TextAlignment="Center"
+                           Foreground="{StaticResource InfoFg}"
+                           FontSize="12"/>
+            </Border>
+
+            <StackPanel Grid.Row="2">
+                <TextBlock Text="Supports OneNote packages, PDF, XPS and local backup copies."
+                           TextWrapping="Wrap"
+                           TextAlignment="Center"
+                           Foreground="{StaticResource TextSecondary}"
+                           FontSize="12"/>
+                <TextBlock Text="© 2026 JLI Software"
+                           Margin="0,8,0,0"
+                           TextAlignment="Center"
+                           Foreground="{StaticResource TextSecondary}"
+                           FontSize="11"/>
+            </StackPanel>
+
+            <Button Grid.Row="3"
+                    Content="Close"
+                    Style="{StaticResource SmallButtonStyle}"
+                    Width="90"
+                    Margin="0,16,0,0"
+                    HorizontalAlignment="Right"
+                    IsDefault="True"
+                    IsCancel="True"
+                    Click="CloseButton_Click"/>
+        </Grid>
+    </Border>
+</Window>

AboutWindow.xaml.cs

@@ -0,0 +1,31 @@
+using System.Reflection;
+using System.Windows;
+
+namespace OneNoteExporter;
+
+public partial class AboutWindow : Window
+{
+    public AboutWindow()
+    {
+        InitializeComponent();
+
+        var assembly = Assembly.GetExecutingAssembly();
+        var informationalVersion = assembly
+            .GetCustomAttribute<AssemblyInformationalVersionAttribute>()?
+            .InformationalVersion;
+        var versionParts = informationalVersion?.Split('+', 2);
+        var version = versionParts is { Length: > 0 } && !string.IsNullOrWhiteSpace(versionParts[0])
+            ? versionParts[0]
+            : assembly.GetName().Version?.ToString(3) ?? "Unknown";
+        var configuration = assembly
+            .GetCustomAttribute<AssemblyConfigurationAttribute>()?
+            .Configuration ?? "Release";
+
+        VersionText.Text = $"Version {version}";
+        BuildText.Text = versionParts is { Length: 2 }
+            ? $"{configuration} build · {versionParts[1][..Math.Min(7, versionParts[1].Length)]}"
+            : $"{configuration} build";
+    }
+
+    private void CloseButton_Click(object sender, RoutedEventArgs e) => Close();
+}

App.xaml

@@ -146,6 +146,27 @@
             </Style.Triggers>
         </Style>
 
+        <!-- Compact header button for About/version information -->
+        <Style x:Key="AboutButtonStyle" TargetType="Button">
+            <Setter Property="Width" Value="30"/>
+            <Setter Property="Height" Value="30"/>
+            <Setter Property="Padding" Value="0"/>
+            <Setter Property="Background" Value="Transparent"/>
+            <Setter Property="BorderBrush" Value="{StaticResource BorderColor}"/>
+            <Setter Property="BorderThickness" Value="1"/>
+            <Setter Property="Foreground" Value="{StaticResource PrimaryBlue}"/>
+            <Setter Property="FontSize" Value="14"/>
+            <Setter Property="FontWeight" Value="Bold"/>
+            <Setter Property="Cursor" Value="Hand"/>
+            <Setter Property="Template" Value="{StaticResource BorderedButtonTemplate}"/>
+            <Style.Triggers>
+                <Trigger Property="IsMouseOver" Value="True">
+                    <Setter Property="Background" Value="#EEF4FF"/>
+                    <Setter Property="BorderBrush" Value="{StaticResource PrimaryBlue}"/>
+                </Trigger>
+            </Style.Triggers>
+        </Style>
+
         <!-- ===== TextBox Style ===== -->
         <Style TargetType="TextBox">
             <Setter Property="Padding"       Value="8,6"/>

App.xaml.cs

@@ -1,5 +1,6 @@
 using System.Windows;
 using System.Windows.Threading;
+using OneNoteExporter.Helpers;
 
 namespace OneNoteExporter;
 
@@ -16,7 +17,9 @@ protected override void OnStartup(StartupEventArgs e)
     private void OnDispatcherUnhandledException(object sender, DispatcherUnhandledExceptionEventArgs e)
     {
         MessageBox.Show(
-            $"An unexpected error occurred:\n\n{e.Exception.Message}",
+            UserFacingError.Describe(
+                e.Exception,
+                "An unexpected error occurred. Please restart the app and try again."),
             "OneNote Exporter – Error",
             MessageBoxButton.OK,
             MessageBoxImage.Error);

CHANGELOG.md

@@ -0,0 +1,10 @@
+# Changelog
+
+## 1.2.0
+
+- Improved reliability with a serialized OneNote COM worker, safe cancellation, and bounded connection recovery.
+- Protected existing backups with staging files and atomic replacement.
+- Added safer PDF/XPS handling for large notebooks, including automatic per-section export.
+- Prevented filename collisions while preserving OneNote section-group folders.
+- Added an About dialog with version and build information.
+- Standardized all user-facing errors, progress messages, and release tooling in English.

CLAUDE.md

@@ -12,8 +12,10 @@ Single-project WPF app, no subprocesses:
 
 ```
 MainWindow.xaml / .xaml.cs   (UI + code-behind)
-    ↕ direct method calls
-Services/OneNoteService.cs   (OneNote COM API wrapper)
+    ↕ async calls
+Services/OneNoteComWorker.cs (serialized STA thread + message pump)
+    ↕ synchronous calls on the owning STA thread
+Services/OneNoteService.cs   (low-level OneNote COM API wrapper)
     ↕ COM API
 OneNote Desktop
 ```
@@ -26,17 +28,19 @@ OneNoteExporterC#/
 ├── OneNoteExporter.sln
 ├── App.xaml                  Global styles (colors, buttons, inputs)
 ├── App.xaml.cs               Global exception handler
+├── AboutWindow.xaml/.cs      About dialog with runtime version/build metadata
 ├── MainWindow.xaml           Full UI layout
 ├── MainWindow.xaml.cs        All UI logic, async export flow
 ├── Models/
 │   └── Models.cs             NotebookInfo, ExportResult, VersionInfo,
 │                             BackupAvailability, NotebookViewModel
 ├── Services/
-│   └── OneNoteService.cs     COM wrapper: GetNotebooks, ExportNotebook,
-│                             ExportAllNotebooks, GetVersionInfo, Dispose
+│   ├── OneNoteComWorker.cs   Dedicated STA owner, serialized async facade
+│   └── OneNoteService.cs     Low-level hierarchy and publish COM calls
 └── Helpers/
-    └── FileHelper.cs         Local backup path, CopyLocalBackup, OpenFolder,
-                              GetDefaultDownloadsPath
+    ├── FileHelper.cs         Local backup path, CopyLocalBackup, OpenFolder,
+    │                         GetDefaultDownloadsPath
+    └── UserFacingError.cs    Stable English error text and language-neutral codes
 ```
 
 ## Development Commands
@@ -52,6 +56,17 @@ dotnet run
 dotnet publish -c Release -r win-x64 --self-contained true
 ```
 
+## Release Asset Naming
+
+Public release assets must use stable, version-independent names so `releases/latest`
+download URLs remain permanent:
+
+- `OneNoteBackupExporter_Setup.exe`
+- `OneNoteBackupExporter_Setup.exe.sha256`
+
+Do not add the version number to public release asset filenames. Keep the semantic version
+in the project, installer metadata, Git tag, GitHub release title, and About dialog instead.
+
 ## Critical Technical Details
 
 ### COM Compatibility
@@ -60,17 +75,25 @@ dotnet publish -c Release -r win-x64 --self-contained true
 - **Do NOT add `<UseWindowsForms>true</UseWindowsForms>`** – causes namespace conflict with the COM `Application` class
 
 ### Threading Model
-- `OneNoteService` methods are synchronous and blocking (COM calls + polling with `Thread.Sleep`)
-- Always call service methods via `Task.Run(...)` from the UI layer
+- `OneNoteComWorker` owns `OneNoteService` and its COM object on one dedicated STA thread
+- All OneNote COM calls are dispatched through that thread's WPF `Dispatcher` message pump
+- Public worker methods are async and serialized; do not wrap them in `Task.Run(...)`
+- Export file polling runs asynchronously outside the STA thread while the serialization gate remains held
 - Use `IProgress<string>` for progress reporting (marshals back to UI thread automatically via `Progress<T>`)
-- Use `CancellationToken` for cooperative cancellation; `ct.WaitHandle.WaitOne(ms)` replaces `Thread.Sleep` in polling loops for cancellation-aware waits
+- Use `CancellationToken` for cooperative cancellation and `Task.Delay(..., ct)` in polling loops
 
 ### Export Process
-1. `OneNoteService` is initialized at window load via `Task.Run(() => new OneNoteService())`
-2. `GetNotebooks()` retrieves all notebooks via `GetHierarchy()` XML parse
-3. `ExportNotebook()` calls `OpenHierarchy()` then `Publish()` with the appropriate `PublishFormat` enum
-4. After `Publish()` returns (immediately), the service polls the output file until size is stable for 10 seconds (file write monitoring)
-5. Timeout: 20 min for local notebooks, 30 min for cloud (SharePoint/OneDrive)
+1. `OneNoteComWorker.CreateAsync()` starts the STA thread and creates `OneNoteService` there
+2. `GetNotebooksAsync()` retrieves all notebooks via `GetHierarchy()` XML parse on the worker
+3. `ExportNotebookAsync()` publishes to a unique same-directory staging file on the STA worker
+4. Recoverable COM/RPC failures get one bounded retry; disconnected COM objects are recreated and validated on the STA thread
+5. Async file polling waits until size is stable for 10 seconds while the STA message pump stays responsive
+6. A successful staging file atomically replaces the final export; previous good backups remain untouched on failure
+7. Timeout: 20 min for local notebooks, 30 min for cloud (SharePoint/OneDrive); polling timeouts are not retried
+8. OneNote does not expose notebook byte size through COM. Whole-notebook PDF/XPS
+   jobs therefore show a preflight choice: automatically split into individual
+   section exports (recommended), switch to `.onepkg`, or explicitly try the whole
+   rendered export anyway
 
 ### Export Formats
 | UI value | PublishFormat | Extension |
@@ -86,23 +109,26 @@ dotnet publish -c Release -r win-x64 --self-contained true
 - When selected in dropdown: all notebooks auto-checked, checkboxes disabled, warning shown
 
 ### OneNote COM Cleanup
-- `OneNoteService.Dispose()` is called in `MainWindow.Window_Closing`
-- `Dispose()` calls `Marshal.ReleaseComObject()` – does NOT kill the OneNote process
+- `OneNoteComWorker.Dispose()` is called in `MainWindow.Window_Closing`
+- The worker releases the COM object on its owning STA thread and does NOT kill OneNote
 - OneNote continues running in background after app closes (by design, avoids "could not be started on last attempt" error)
 
 ### Known COM Errors
 | HResult | Cause | Action |
 |---|---|---|
-| `0x8004201A` | Password-protected sections or offline | Show message, suggest unlocking |
-| `0x800706BA` | RPC timeout (large notebook, PDF/XPS) | Suggest .onepkg format |
+| `0x8004201A` | Export file already exists | Report the target-file collision |
+| `0x8004201D` | Notebook is not fully synchronized | Ask the user to finish sync |
+| `0x80042023` | OneNote internal timeout | Report timeout; suggest .onepkg for large PDF/XPS jobs |
+| `0x80042030` | A modal OneNote dialog blocks COM | Ask the user to close the dialog |
+| `0x800706BA` | OneNote RPC server unavailable/disconnected | Reconnect once, then report actionable COM guidance |
 | `0x80070005` | Access denied | Check permissions |
 | `0x80042010` | Notebook not accessible | Open in OneNote first |
 
 ## UI Design
 
 ### Layout (3-row Grid)
 ```
-Row 0 (Auto):   Header – title (#0078d7) + version badge (dynamic color)
+Row 0 (Auto):   Header – title, OneNote status badge and About/version button
 Row 1 (*):      Notebook list (ScrollViewer + ItemsControl with CheckBoxes)
 Row 2 (Auto):   Export section (path, format dropdown, warning, buttons, status)
 ```
@@ -121,7 +147,10 @@ Row 2 (Auto):   Export section (path, format dropdown, warning, buttons, status)
 - List background: `#F8F9FA`
 
 ### UI Language
-**English** – all UI strings are in English (matching the original Go/Wails frontend).
+**English** – all user-facing UI, error, progress, dialog, status, and completion strings
+must remain in English. Do not display raw `Exception.Message` values because Windows and
+OneNote COM messages follow the operating-system language. Use `UserFacingError` and a
+language-neutral HRESULT/error code while keeping internal diagnostic output non-sensitive.
 
 ### Key Behaviors
 - Export button disabled until ≥1 notebook selected; text = `"Export N notebook(s)"`

Helpers/FileHelper.cs

@@ -63,7 +63,9 @@ public static BackupAvailability CheckLocalBackupAvailable()
             {
                 Available = false,
                 Reason    = "read_error",
-                Message   = $"Error reading backup folder: {ex.Message}",
+                Message   = UserFacingError.Describe(
+                    ex,
+                    "The OneNote backup folder could not be read."),
                 Path      = backupPath
             };
         }
@@ -104,7 +106,13 @@ public static ExportResult CopyLocalBackup(string destPath)
         }
         catch (Exception ex)
         {
-            return new ExportResult { Success = false, Message = $"Error copying backup: {ex.Message}" };
+            return new ExportResult
+            {
+                Success = false,
+                Message = UserFacingError.Describe(
+                    ex,
+                    "The local OneNote backup could not be copied.")
+            };
         }
     }
 
@@ -122,7 +130,8 @@ public static void OpenFolder(string path)
         }
         catch (Exception ex)
         {
-            Debug.WriteLine($"Failed to open folder: {ex.Message}");
+            Debug.WriteLine(
+                UserFacingError.Describe(ex, "The destination folder could not be opened."));
         }
     }