Found solution to multi-threading issue at application startup and created draft of startup procedure.

SafeExamBrowser.Core/Behaviour/StartupController.cs

@@ -7,6 +7,8 @@
  */
 
 using System;
+using System.Collections.Generic;
+using System.Linq;
 using System.Threading;
 using SafeExamBrowser.Contracts.Behaviour;
 using SafeExamBrowser.Contracts.Configuration;
@@ -27,6 +29,23 @@ namespace SafeExamBrowser.Core.Behaviour
 		private IText text;
 		private IUiElementFactory uiFactory;
 
+		private IEnumerable<Action> StartupOperations
+		{
+			get
+			{
+				yield return InitializeApplicationLog;
+				yield return HandleCommandLineArguments;
+				yield return DetectOperatingSystem;
+				yield return EstablishWcfServiceConnection;
+				yield return DeactivateWindowsFeatures;
+				yield return InitializeProcessMonitoring;
+				yield return InitializeWorkArea;
+				yield return InitializeTaskbar;
+				yield return InitializeBrowser;
+				yield return FinishInitialization;
+			}
+		}
+
 		public StartupController(IApplicationInfo browserInfo, ILogger logger, IMessageBox messageBox, ISettings settings, ISplashScreen splashScreen, ITaskbar taskbar, IText text, IUiElementFactory uiFactory)
 		{
 			this.browserInfo = browserInfo;
@@ -43,47 +62,15 @@ namespace SafeExamBrowser.Core.Behaviour
 		{
 			try
 			{
-				logger.Log(settings.LogHeader);
+				foreach (var operation in StartupOperations)
-				logger.Log($"{Environment.NewLine}# Application started at {DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff")}{Environment.NewLine}");
+				{
-				logger.Info("Initiating startup procedure.");
+					operation();
-				logger.Subscribe(splashScreen);
-
-				splashScreen.SetMaxProgress(3);
-				logger.Info("Initializing browser.");
-
-				var browserButton = uiFactory.CreateButton(browserInfo);
-
-				taskbar.AddButton(browserButton);
 
 					splashScreen.UpdateProgress();
 
-				// TODO (depending on specification):
+					// TODO: Remove!
-				// - WCF service connection, termination if not available
+					Thread.Sleep(250);
-
+				}
-				// TODO:
-				// - Parse command line arguments
-				// - Detecting operating system and log that information
-				// - Logging of all running processes
-				// - Setting of wallpaper
-				// - Initialization of taskbar
-				// - Killing explorer.exe
-				// - Minimizing all open windows
-				// - Emptying clipboard
-				// - Activation of process monitoring
-
-				Thread.Sleep(1000);
-
-				splashScreen.UpdateProgress();
-				logger.Info("Baapa-dee boopa-dee!");
-
-				Thread.Sleep(1000);
-
-				splashScreen.UpdateProgress();
-				logger.Info("Closing splash screen.");
-
-				Thread.Sleep(1000);
-				logger.Unsubscribe(splashScreen);
-				logger.Info("Application successfully initialized!");
 
 				return true;
 			}
@@ -95,5 +82,88 @@ namespace SafeExamBrowser.Core.Behaviour
 				return false;
 			}
 		}
+
+		private void InitializeApplicationLog()
+		{
+			logger.Log(settings.LogHeader);
+			logger.Log($"{Environment.NewLine}# Application started at {DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff")}{Environment.NewLine}");
+			logger.Info("Initiating startup procedure.");
+			logger.Subscribe(splashScreen);
+
+			splashScreen.SetMaxProgress(StartupOperations.Count());
+		}
+
+		private void HandleCommandLineArguments()
+		{
+			logger.Info("Parsing command line arguments.");
+
+			// TODO
+		}
+
+		private void DetectOperatingSystem()
+		{
+			logger.Info("Detecting operating system.");
+
+			// TODO
+		}
+
+		private void EstablishWcfServiceConnection()
+		{
+			logger.Info("Establishing connection to WCF service.");
+
+			// TODO
+		}
+
+		private void DeactivateWindowsFeatures()
+		{
+			logger.Info("Deactivating Windows Update.");
+
+			// TODO
+
+			logger.Info("Disabling lock screen options.");
+
+			// TODO
+		}
+
+		private void InitializeProcessMonitoring()
+		{
+			logger.Info("Initializing process monitoring.");
+
+			// TODO
+		}
+
+		private void InitializeWorkArea()
+		{
+			logger.Info("Initializing work area.");
+
+			// TODO
+			// - Killing explorer.exe
+			// - Minimizing all open windows
+			// - Emptying clipboard
+		}
+
+		private void InitializeTaskbar()
+		{
+			logger.Info("Initializing taskbar.");
+
+			// TODO
+		}
+
+		private void InitializeBrowser()
+		{
+			logger.Info("Initializing browser.");
+
+			var browserButton = uiFactory.CreateButton(browserInfo);
+
+			// TODO
+
+			taskbar.AddButton(browserButton);
+		}
+
+		private void FinishInitialization()
+		{
+			logger.Info("Application successfully initialized!");
+			logger.Unsubscribe(splashScreen);
+		}
 	}
 }

SafeExamBrowser.UserInterface/SplashScreen.xaml.cs

@@ -22,14 +22,7 @@ namespace SafeExamBrowser.UserInterface
 		public SplashScreen(ISettings settings)
 		{
 			InitializeComponent();
-
+			InitializeSplashScreen(settings);
-			StatusTextBlock.DataContext = model;
-			ProgressBar.DataContext = model;
-
-			InfoTextBlock.Inlines.Add(new Run($"Version {settings.ProgramVersion}") { FontStyle = FontStyles.Italic });
-			InfoTextBlock.Inlines.Add(new LineBreak());
-			InfoTextBlock.Inlines.Add(new LineBreak());
-			InfoTextBlock.Inlines.Add(new Run(settings.CopyrightInfo) { FontSize = 10 });
 		}
 
 		public void Notify(ILogContent content)
@@ -49,5 +42,19 @@ namespace SafeExamBrowser.UserInterface
 		{
 			model.CurrentProgress += amount;
 		}
+
+		private void InitializeSplashScreen(ISettings settings)
+		{
+			InfoTextBlock.Inlines.Add(new Run($"Version {settings.ProgramVersion}") { FontStyle = FontStyles.Italic });
+			InfoTextBlock.Inlines.Add(new LineBreak());
+			InfoTextBlock.Inlines.Add(new LineBreak());
+			InfoTextBlock.Inlines.Add(new Run(settings.CopyrightInfo) { FontSize = 10 });
+			
+			StatusTextBlock.DataContext = model;
+			ProgressBar.DataContext = model;
+
+			// To prevent the progress bar going from max to min value at startup...
+			model.MaxProgress = 1;
+		}
 	}
 }

SafeExamBrowser/App.cs

@@ -15,7 +15,7 @@ namespace SafeExamBrowser
 	public class App : Application
 	{
 		private static readonly Mutex mutex = new Mutex(true, "safe_exam_browser_single_instance_mutex");
-		private CompositionRoot instances;
+		private CompositionRoot instances = new CompositionRoot();
 
 		[STAThread]
 		public static void Main()
@@ -51,17 +51,8 @@ namespace SafeExamBrowser
 		{
 			base.OnStartup(e);
 
-			var initializationThread = new Thread(Initialize);
+			ShowSplashScreen();
-
+			Initialize();
-			instances = new CompositionRoot();
-			instances.BuildObjectGraph();
-			instances.SplashScreen.Show();
-
-			MainWindow = instances.SplashScreen;
-
-			initializationThread.SetApartmentState(ApartmentState.STA);
-			initializationThread.Name = "Initialization Thread";
-			initializationThread.Start();
 		}
 
 		protected override void OnExit(ExitEventArgs e)
@@ -73,22 +64,43 @@ namespace SafeExamBrowser
 
 		private void Initialize()
 		{
+			instances.BuildObjectGraph();
+
 			var success = instances.StartupController.TryInitializeApplication();
 
 			if (success)
-			{
-				Dispatcher.Invoke(() =>
 			{
 				MainWindow = instances.Taskbar;
 				MainWindow.Show();
-				});
 			}
 			else
 			{
-				Dispatcher.Invoke(Shutdown);
+				Shutdown();
 			}
 
-			Dispatcher.Invoke(instances.SplashScreen.Close);
+			instances.SplashScreen?.Dispatcher.InvokeAsync(instances.SplashScreen.Close);
+		}
+
+		private void ShowSplashScreen()
+		{
+			var splashReadyEvent = new AutoResetEvent(false);
+			var splashScreenThread = new Thread(() =>
+			{
+				instances.SplashScreen = new UserInterface.SplashScreen(instances.Settings);
+				instances.SplashScreen.Closed += (o, args) => instances.SplashScreen.Dispatcher.InvokeShutdown();
+				instances.SplashScreen.Show();
+
+				splashReadyEvent.Set();
+
+				System.Windows.Threading.Dispatcher.Run();
+			});
+
+			splashScreenThread.SetApartmentState(ApartmentState.STA);
+			splashScreenThread.Name = "Splash Screen Thread";
+			splashScreenThread.IsBackground = true;
+			splashScreenThread.Start();
+
+			splashReadyEvent.WaitOne();
 		}
 	}
 }

SafeExamBrowser/CompositionRoot.cs

@@ -8,6 +8,10 @@
 
 using SafeExamBrowser.Browser;
 using SafeExamBrowser.Contracts.Behaviour;
+using SafeExamBrowser.Contracts.Configuration;
+using SafeExamBrowser.Contracts.I18n;
+using SafeExamBrowser.Contracts.Logging;
+using SafeExamBrowser.Contracts.UserInterface;
 using SafeExamBrowser.Core.Behaviour;
 using SafeExamBrowser.Core.Configuration;
 using SafeExamBrowser.Core.I18n;
@@ -18,27 +22,35 @@ namespace SafeExamBrowser
 {
 	internal class CompositionRoot
 	{
-		public IShutdownController ShutdownController { get; set; }
+		private IApplicationInfo browserInfo;
-		public IStartupController StartupController { get; private set; }
+		private IMessageBox messageBox;
+		private ILogger logger;
+		private IUiElementFactory uiFactory;
+		private IText text;
 
-		public SplashScreen SplashScreen { get; private set; }
+		public ISettings Settings { get; private set; }
+		public IShutdownController ShutdownController { get; private set; }
+		public IStartupController StartupController { get; private set; }
+		public SplashScreen SplashScreen { get; set; }
 		public Taskbar Taskbar { get; private set; }
 
+		public CompositionRoot()
+		{
+			browserInfo = new BrowserApplicationInfo();
+			messageBox = new WpfMessageBox();
+			logger = new Logger();
+			Settings = new Settings();
+			Taskbar = new Taskbar();
+			uiFactory = new UiElementFactory();
+		}
+
 		public void BuildObjectGraph()
 		{
-			var browserInfo = new BrowserApplicationInfo();
+			logger.Subscribe(new LogFileWriter(Settings));
-			var messageBox = new WpfMessageBox();
-			var settings = new Settings();
-			var logger = new Logger();
-			var text = new Text(new XmlTextResource());
-			var uiFactory = new UiElementFactory();
 
-			logger.Subscribe(new LogFileWriter(settings));
+			text = new Text(new XmlTextResource());
-
-			Taskbar = new Taskbar();
-			SplashScreen = new SplashScreen(settings);
 			ShutdownController = new ShutdownController(logger, messageBox, text);
-			StartupController = new StartupController(browserInfo, logger, messageBox, settings, SplashScreen, Taskbar, text, uiFactory);
+			StartupController = new StartupController(browserInfo, logger, messageBox, Settings, SplashScreen, Taskbar, text, uiFactory);
 		}
 	}
 }