diff --git a/SafeExamBrowser.Applications.UnitTests/ApplicationFactoryTests.cs b/SafeExamBrowser.Applications.UnitTests/ApplicationFactoryTests.cs
index 08e5effd..f65f0352 100644
--- a/SafeExamBrowser.Applications.UnitTests/ApplicationFactoryTests.cs
+++ b/SafeExamBrowser.Applications.UnitTests/ApplicationFactoryTests.cs
@@ -60,13 +60,16 @@ namespace SafeExamBrowser.Applications.UnitTests
 		[TestMethod]
 		public void MustCorrectlyReadPathFromRegistry()
 		{
-			var o = default(object);
+			object o = @"C:\Some\Registry\Path";
 			var settings = new WhitelistApplication
 			{
 				DisplayName = "Windows Command Prompt",
 				ExecutableName = "cmd.exe",
+				ExecutablePath = @"C:\Some\Path"
 			};
 
+			registry.Setup(r => r.TryRead(It.Is<string>(s => s.Contains(RegistryValue.MachineHive.AppPaths_Key)), It.Is<string>(s => s == "Path"), out o)).Returns(true);
+
 			var result = sut.TryCreate(settings, out var application);
 
 			registry.Verify(r => r.TryRead(It.Is<string>(s => s.Contains(RegistryValue.MachineHive.AppPaths_Key)), It.Is<string>(s => s == "Path"), out o), Times.Once);
@@ -91,6 +94,22 @@ namespace SafeExamBrowser.Applications.UnitTests
 			Assert.IsNull(application);
 		}
 
+		[TestMethod]
+		public void MustFailGracefullyWhenPathIsInvalid()
+		{
+			var settings = new WhitelistApplication
+			{
+				ExecutableName = "asdfg(/ç)&=%\"fsdg..exe..",
+				ExecutablePath = "[]#°§¬#°¢@tu03450'w89tz!$£äöüèé:"
+			};
+
+			var result = sut.TryCreate(settings, out _);
+
+			logger.Verify(l => l.Error(It.IsAny<string>(), It.IsAny<Exception>()), Times.AtLeastOnce);
+
+			Assert.AreEqual(FactoryResult.NotFound, result);
+		}
+
 		[TestMethod]
 		public void MustFailGracefullyAndIndicateThatErrorOccurred()
 		{
diff --git a/SafeExamBrowser.Applications.UnitTests/ExternalApplicationTests.cs b/SafeExamBrowser.Applications.UnitTests/ExternalApplicationTests.cs
index 51e85bc8..25655679 100644
--- a/SafeExamBrowser.Applications.UnitTests/ExternalApplicationTests.cs
+++ b/SafeExamBrowser.Applications.UnitTests/ExternalApplicationTests.cs
@@ -51,10 +51,10 @@ namespace SafeExamBrowser.Applications.UnitTests
 		[TestMethod]
 		public void GetWindows_MustCorrectlyReturnOpenWindows()
 		{
-			var sync = new AutoResetEvent(false);
+			var openWindows = new List<IntPtr> { new IntPtr(123), new IntPtr(234), new IntPtr(456), new IntPtr(345), new IntPtr(567), new IntPtr(789), };
 			var process1 = new Mock<IProcess>();
 			var process2 = new Mock<IProcess>();
-			var openWindows = new List<IntPtr> { new IntPtr(123), new IntPtr(234), new IntPtr(456), new IntPtr(345), new IntPtr(567), new IntPtr(789), };
+			var sync = new AutoResetEvent(false);
 
 			nativeMethods.Setup(n => n.GetOpenWindows()).Returns(openWindows);
 			nativeMethods.Setup(n => n.GetProcessIdFor(It.Is<IntPtr>(p => p == new IntPtr(234)))).Returns(1234);
@@ -88,6 +88,7 @@ namespace SafeExamBrowser.Applications.UnitTests
 		public void Initialize_MustInitializeCorrectly()
 		{
 			settings.AutoStart = new Random().Next(2) == 1;
+			settings.Description = "Some Description";
 
 			sut.Initialize();
 
@@ -123,6 +124,40 @@ namespace SafeExamBrowser.Applications.UnitTests
 			processFactory.Verify(f => f.StartNew(It.IsAny<string>(), It.IsAny<string[]>()), Times.Once);
 		}
 
+		[TestMethod]
+		public void Start_MustRemoveInstanceCorrectlyWhenTerminated()
+		{
+			var eventRaised = false;
+			var openWindows = new List<IntPtr> { new IntPtr(123), new IntPtr(234), new IntPtr(456), new IntPtr(345), new IntPtr(567), new IntPtr(789), };
+			var process = new Mock<IProcess>();
+			var sync = new AutoResetEvent(false);
+
+			nativeMethods.Setup(n => n.GetOpenWindows()).Returns(openWindows);
+			nativeMethods.Setup(n => n.GetProcessIdFor(It.Is<IntPtr>(p => p == new IntPtr(234)))).Returns(1234);
+			process.Setup(p => p.TryClose(It.IsAny<int>())).Returns(false);
+			process.Setup(p => p.TryKill(It.IsAny<int>())).Returns(true);
+			process.SetupGet(p => p.Id).Returns(1234);
+			processFactory.Setup(f => f.StartNew(It.IsAny<string>(), It.IsAny<string[]>())).Returns(process.Object);
+
+			sut.WindowsChanged += () =>
+			{
+				eventRaised = true;
+				sync.Set();
+			};
+
+			sut.Initialize();
+			sut.Start();
+
+			sync.WaitOne();
+
+			Assert.AreEqual(1, sut.GetWindows().Count());
+
+			process.Raise(p => p.Terminated += null, default(int));
+
+			Assert.IsTrue(eventRaised);
+			Assert.AreEqual(0, sut.GetWindows().Count());
+		}
+
 		[TestMethod]
 		public void Terminate_MustStopAllInstancesCorrectly()
 		{
diff --git a/SafeExamBrowser.Applications.UnitTests/ExternalApplicationWindowTests.cs b/SafeExamBrowser.Applications.UnitTests/ExternalApplicationWindowTests.cs
new file mode 100644
index 00000000..5f903364
--- /dev/null
+++ b/SafeExamBrowser.Applications.UnitTests/ExternalApplicationWindowTests.cs
@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2023 ETH Zürich, Educational Development and Technology (LET)
+ * 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+using System;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Moq;
+using SafeExamBrowser.Core.Contracts.Resources.Icons;
+using SafeExamBrowser.WindowsApi.Contracts;
+
+namespace SafeExamBrowser.Applications.UnitTests
+{
+	[TestClass]
+	public class ExternalApplicationWindowTests
+	{
+		private IntPtr handle;
+		private NativeIconResource icon;
+		private Mock<INativeMethods> nativeMethods;
+
+		private ExternalApplicationWindow sut;
+
+		[TestInitialize]
+		public void Initialize()
+		{
+			handle = new IntPtr(123);
+			icon = new NativeIconResource();
+			nativeMethods = new Mock<INativeMethods>();
+
+			sut = new ExternalApplicationWindow(icon, nativeMethods.Object, handle);
+		}
+
+		[TestMethod]
+		public void Activate_MustCorrectlyActivateWindow()
+		{
+			sut.Activate();
+			nativeMethods.Verify(n => n.ActivateWindow(It.Is<IntPtr>(h => h == handle)));
+		}
+
+		[TestMethod]
+		public void Update_MustCorrectlyUpdateWindow()
+		{
+			var iconChanged = false;
+			var titleChanged = false;
+
+			nativeMethods.Setup(m => m.GetWindowIcon(It.IsAny<IntPtr>())).Returns(new IntPtr(456));
+
+			sut.IconChanged += (_) => iconChanged = true;
+			sut.TitleChanged += (_) => titleChanged = true;
+
+			sut.Update();
+
+			Assert.IsTrue(iconChanged);
+			Assert.IsTrue(titleChanged);
+		}
+	}
+}
diff --git a/SafeExamBrowser.Applications.UnitTests/SafeExamBrowser.Applications.UnitTests.csproj b/SafeExamBrowser.Applications.UnitTests/SafeExamBrowser.Applications.UnitTests.csproj
index ad9cf941..9b91d040 100644
--- a/SafeExamBrowser.Applications.UnitTests/SafeExamBrowser.Applications.UnitTests.csproj
+++ b/SafeExamBrowser.Applications.UnitTests/SafeExamBrowser.Applications.UnitTests.csproj
@@ -84,6 +84,7 @@
     <Compile Include="ApplicationFactoryTests.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="ExternalApplicationTests.cs" />
+    <Compile Include="ExternalApplicationWindowTests.cs" />
   </ItemGroup>
   <ItemGroup>
     <None Include="app.config" />