#1822 - Fix the startup crash after auto-upgrade by loading the library only after InteropFactory assembly resolution is ready, checking that Microsoft.EntityFrameworkCore.Sqlite.dll is present in the install folder, and showing a clear reinstall message instead of a generic "Unexpected error" when that still fails.

Source/LibationAvalonia/App.axaml.cs

@@ -73,6 +73,7 @@ public class App : Application
 		{
 			// setup succeeded or wasn't needed and LibationFiles are valid
 			RunMigrations(config);
+			StartupAssemblyBootstrap.PrepareForBackgroundDataAccess();
 			LibraryTask = Task.Run(() => DbContexts.GetLibrary_Flat_NoTracking(includeParents: true));
 			ShowMainWindow(desktop);
 		}
@@ -142,8 +143,22 @@ public class App : Application
 	{
 		if (LibraryTask is not null && MainWindow is not null)
 		{
-			List<DataLayer.LibraryBook> library = await LibraryTask;
-			await Dispatcher.UIThread.InvokeAsync(() => MainWindow.OnLibraryLoadedAsync(library));
+			try
+			{
+				List<DataLayer.LibraryBook> library = await LibraryTask;
+				await Dispatcher.UIThread.InvokeAsync(() => MainWindow.OnLibraryLoadedAsync(library));
+			}
+			catch (Exception ex) when (StartupAssemblyBootstrap.IsMissingDependencyAssembly(ex))
+			{
+				Serilog.Log.Logger.Error(ex, "Failed to load library at startup");
+				await MessageBox.Show(
+					MainWindow,
+					StartupAssemblyBootstrap.GetLibraryLoadFailureMessage(),
+					"Library load failed",
+					MessageBoxButtons.OK,
+					MessageBoxIcon.Error);
+				await Dispatcher.UIThread.InvokeAsync(() => MainWindow.OnLibraryLoadedAsync([]));
+			}
 		}
 	}
 }

Source/LibationAvalonia/Program.cs

@@ -56,8 +56,7 @@ static class Program
 			if (config.LibationFiles.SettingsAreValid)
 			{
 				App.RunMigrations(config);
-				// When running inside Snap, UseWebView getter returns false to avoid portal/sandbox crashes (e.g. github ticket #1664).
-				//Start loading the library before loading the main form
+				StartupAssemblyBootstrap.PrepareForBackgroundDataAccess();
 				App.LibraryTask = Task.Run(() => DbContexts.GetLibrary_Flat_NoTracking(includeParents: true));
 			}
 			BuildAvaloniaApp()?.StartWithClassicDesktopLifetime([], ShutdownMode.OnExplicitShutdown);

Source/LibationFileManager/StartupAssemblyBootstrap.cs

@@ -0,0 +1,62 @@
+using System;
+using System.IO;
+
+namespace LibationFileManager;
+
+/// <summary>
+/// Ensures OS interop assembly resolution and required dependency files are ready before background library load.
+/// </summary>
+public static class StartupAssemblyBootstrap
+{
+	public const string EntityFrameworkCoreSqliteAssemblyFileName = "Microsoft.EntityFrameworkCore.Sqlite.dll";
+
+	/// <summary>
+	/// Registers <see cref="InteropFactory"/> assembly resolution and verifies required install-folder assemblies exist.
+	/// Call before <c>Task.Run</c> loads the library or opens the database on a thread-pool thread.
+	/// </summary>
+	public static void PrepareForBackgroundDataAccess()
+	{
+		_ = InteropFactory.InteropFunctionsType;
+		ValidateEntityFrameworkCoreSqlitePresent();
+	}
+
+	public static string GetLibraryLoadFailureMessage() =>
+		$"""
+		Libation could not load its database components (Entity Framework Core for SQLite).
+
+		This often happens after an incomplete in-app upgrade. Quit Libation completely, then install a fresh copy of the latest release to a new folder (do not overlay files on top of the old install).
+
+		Install folder:
+		{Configuration.ProcessDirectory}
+
+		Expected file:
+		{Path.Combine(Configuration.ProcessDirectory, EntityFrameworkCoreSqliteAssemblyFileName)}
+		""";
+
+	public static bool IsMissingDependencyAssembly(Exception ex)
+	{
+		for (var current = ex; current is not null; current = current.InnerException)
+		{
+			if (current is not FileNotFoundException and not FileLoadException)
+				continue;
+
+			var name = (current as FileNotFoundException)?.FileName ?? current.Message;
+			if (name.Contains("EntityFrameworkCore", StringComparison.OrdinalIgnoreCase)
+				|| name.Contains("Microsoft.Data.Sqlite", StringComparison.OrdinalIgnoreCase))
+				return true;
+		}
+
+		return false;
+	}
+
+	private static void ValidateEntityFrameworkCoreSqlitePresent()
+	{
+		var path = Path.Combine(Configuration.ProcessDirectory, EntityFrameworkCoreSqliteAssemblyFileName);
+		if (File.Exists(path))
+			return;
+
+		throw new FileNotFoundException(
+			$"Required file '{EntityFrameworkCoreSqliteAssemblyFileName}' was not found in the Libation install folder.{Environment.NewLine}{Environment.NewLine}{GetLibraryLoadFailureMessage()}",
+			path);
+	}
+}

Source/LibationWinForms/Program.cs

@@ -4,6 +4,7 @@ using DataLayer;
 using LibationFileManager;
 using LibationUiBase;
 using LibationWinForms.Dialogs;
+using Serilog;
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -58,26 +59,31 @@ static class Program
 			// migrations which require Forms or are long-running
 			RunWindowsOnlyMigrations(config);
 
-			//*******************************************************************//
-			//                                                                   //
-			//  Start loading the library as soon as possible                    //
-			//                                                                   //
-			//  Before calling anything else, including subscribing to events,   //
-			//  to ensure database exists. If we wait and let it happen lazily,  //
-			//  race conditions and errors are likely during new installs        //
-			//                                                                   //
-			//*******************************************************************//
-			libraryLoadTask = Task.Run(() => DbContexts.GetLibrary_Flat_NoTracking(includeParents: true));
-
 			MessageBoxLib.VerboseLoggingWarning_ShowIfTrue();
 
-			// logging is init'd here
+			// logging is init'd here (also initializes InteropFactory via logStartupState)
 			LibationScaffolding.RunPostMigrationScaffolding(Variety.Classic, config);
+
+			//*******************************************************************//
+			//                                                                   //
+			//  Start loading the library as soon as possible after logging    //
+			//  and InteropFactory assembly resolution are ready.                //
+			//                                                                   //
+			//*******************************************************************//
+			StartupAssemblyBootstrap.PrepareForBackgroundDataAccess();
+			libraryLoadTask = Task.Run(() => DbContexts.GetLibrary_Flat_NoTracking(includeParents: true));
 		}
 		catch (Exception ex)
 		{
-			var title = "Fatal error, pre-logging";
-			var body = "An unrecoverable error occurred. Since this error happened before logging could be initialized, this error can not be written to the log file.";
+			if (Configuration.Instance.SerilogInitialized)
+				Log.Error(ex, "Fatal error during startup");
+
+			var (title, body) = StartupAssemblyBootstrap.IsMissingDependencyAssembly(ex)
+				? ("Library load failed", StartupAssemblyBootstrap.GetLibraryLoadFailureMessage())
+				: (
+					"Fatal error, pre-logging",
+					"An unrecoverable error occurred. Since this error happened before logging could be initialized, this error can not be written to the log file.");
+
 			try
 			{
 				MessageBoxLib.ShowAdminAlert(null, body, title, ex);
@@ -93,7 +99,7 @@ static class Program
 		postLoggingGlobalExceptionHandling();
 
 		form1 = new Form1();
-		form1.Load += async (_, _) => await form1.InitLibraryAsync(await libraryLoadTask);
+		form1.Load += async (_, _) => await LoadLibraryIntoFormAsync(form1, libraryLoadTask);
 		Application.Run(form1);
 	}
 
@@ -181,6 +187,24 @@ static class Program
 		}
 	}
 
+	private static async Task LoadLibraryIntoFormAsync(Form1 form, Task<List<LibraryBook>> libraryLoadTask)
+	{
+		try
+		{
+			await form.InitLibraryAsync(await libraryLoadTask);
+		}
+		catch (Exception ex) when (StartupAssemblyBootstrap.IsMissingDependencyAssembly(ex))
+		{
+			Log.Error(ex, "Failed to load library at startup");
+			MessageBoxLib.ShowAdminAlert(
+				form,
+				StartupAssemblyBootstrap.GetLibraryLoadFailureMessage(),
+				"Library load failed",
+				ex);
+			await form.InitLibraryAsync([]);
+		}
+	}
+
 	private static void postLoggingGlobalExceptionHandling()
 	{
 		// this line is all that's needed for strict handling