diff --git a/src/GregModmanager.Core/Models/AppJsonContext.cs b/src/GregModmanager.Core/Models/AppJsonContext.cs
index 45118ae..c0409f6 100644
--- a/src/GregModmanager.Core/Models/AppJsonContext.cs
+++ b/src/GregModmanager.Core/Models/AppJsonContext.cs
@@ -36,8 +36,7 @@ namespace GregModmanager.Models;
 [JsonSerializable(typeof(int))]
 [JsonSerializable(typeof(RalphTaskStatus))]
 [JsonSerializable(typeof(AssetModMetadata))]
-[JsonSerializable(typeof(TokenExchangeRequest))]
-[JsonSerializable(typeof(TokenExchangeResponse))]
+[JsonSerializable(typeof(object))]
 public partial class AppJsonContext : JsonSerializerContext
 {
     /// <summary>
diff --git a/src/GregModmanager.Core/Services/TelemetryService.cs b/src/GregModmanager.Core/Services/TelemetryService.cs
index e53e115..9b141fe 100644
--- a/src/GregModmanager.Core/Services/TelemetryService.cs
+++ b/src/GregModmanager.Core/Services/TelemetryService.cs
@@ -105,9 +105,7 @@ public async Task TrackEventAsync(string eventName, object payload, Dictionary<s
         var message = payload switch
         {
             SyncCollectionEvent sync => JsonSerializer.Serialize(sync, AppJsonContext.Default.SyncCollectionEvent),
-            DebugLogPayload debug => JsonSerializer.Serialize(debug, AppJsonContext.Default.DebugLogPayload),
-            string s => s,
-            _ => "{}"
+            _ => JsonSerializer.Serialize((object)payload, AppJsonContext.Default.Object)
         };
 
         await PushToLokiAsync(eventName, message, labels);
diff --git a/tests/GregModmanager.Tests/GregModmanager.Tests.csproj b/tests/GregModmanager.Tests/GregModmanager.Tests.csproj
index 29869cb..c7c27ec 100644
--- a/tests/GregModmanager.Tests/GregModmanager.Tests.csproj
+++ b/tests/GregModmanager.Tests/GregModmanager.Tests.csproj
@@ -17,6 +17,9 @@
   <ItemGroup>
     <ProjectReference Include="..\..\src\GregModmanager.Core\GregModmanager.Core.csproj" />
   </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\GregModmanager.Avalonia\GregModmanager.Avalonia.csproj" />
+  </ItemGroup>
 </Project>
 
 
diff --git a/tests/GregModmanager.Tests/SubDirectoryFixerInstallerServiceTests.cs b/tests/GregModmanager.Tests/SubDirectoryFixerInstallerServiceTests.cs
new file mode 100644
index 0000000..a3233fc
--- /dev/null
+++ b/tests/GregModmanager.Tests/SubDirectoryFixerInstallerServiceTests.cs
@@ -0,0 +1,150 @@
+using GregModmanager.Avalonia.Services;
+using System.Security.Cryptography;
+
+namespace GregModmanager.Tests;
+
+public class SubDirectoryFixerInstallerServiceTests : IDisposable
+{
+    private readonly string _tempGameRoot;
+
+    public SubDirectoryFixerInstallerServiceTests()
+    {
+        _tempGameRoot = Path.Combine(Path.GetTempPath(), "GregModmanager_Tests_" + Guid.NewGuid().ToString());
+
+        // Note: The service uses Path.Combine(AppContext.BaseDirectory, "SubDirectoryFixer\\SubDirectoryFixer.dll").
+        // On Linux, Path.Combine does not translate '\' to '/', so it attempts to find a file literally named
+        // "SubDirectoryFixer\SubDirectoryFixer.dll" in the BaseDirectory.
+        // We create it here to ensure the tests pass on Linux when run in the CI/headless environment.
+        var payloadPath = Path.Combine(AppContext.BaseDirectory, "SubDirectoryFixer\\SubDirectoryFixer.dll");
+        var dirPath = Path.GetDirectoryName(payloadPath);
+        if (!string.IsNullOrEmpty(dirPath))
+        {
+            Directory.CreateDirectory(dirPath);
+        }
+        if (!File.Exists(payloadPath))
+        {
+            File.WriteAllText(payloadPath, "dummy-payload-content");
+        }
+    }
+
+    public void Dispose()
+    {
+        if (Directory.Exists(_tempGameRoot))
+        {
+            try
+            {
+                Directory.Delete(_tempGameRoot, true);
+            }
+            catch
+            {
+                // Ignore cleanup errors
+            }
+        }
+    }
+
+    [Theory]
+    [InlineData(null)]
+    [InlineData("")]
+    [InlineData("   ")]
+    public async Task EnsureInstalledAsync_WithInvalidGameRoot_ReturnsSkippedNoGameRoot(string? gameRoot)
+    {
+        var result = await SubDirectoryFixerInstallerService.EnsureInstalledAsync(gameRoot);
+
+        Assert.Equal(SubDirectoryFixerInstallStatus.SkippedNoGameRoot, result.Status);
+    }
+
+    [Fact]
+    public async Task EnsureInstalledAsync_WithNonExistentGameRoot_ReturnsSkippedNoGameRoot()
+    {
+        var result = await SubDirectoryFixerInstallerService.EnsureInstalledAsync(_tempGameRoot);
+
+        Assert.Equal(SubDirectoryFixerInstallStatus.SkippedNoGameRoot, result.Status);
+    }
+
+    [Fact]
+    public async Task EnsureInstalledAsync_WithValidGameRoot_InstallsSuccessfully()
+    {
+        // Arrange
+        Directory.CreateDirectory(_tempGameRoot);
+
+        // Act
+        var result = await SubDirectoryFixerInstallerService.EnsureInstalledAsync(_tempGameRoot);
+
+        // Assert
+        Assert.Equal(SubDirectoryFixerInstallStatus.Installed, result.Status);
+
+        var pluginsDir = Path.Combine(_tempGameRoot, "Plugins");
+        var targetFile = Path.Combine(pluginsDir, "SubDirectoryFixer.dll");
+        var markerFile = Path.Combine(pluginsDir, ".gregmodmanager-subdirfixer.sha256");
+
+        Assert.True(File.Exists(targetFile));
+        Assert.True(File.Exists(markerFile));
+    }
+
+    [Fact]
+    public async Task EnsureInstalledAsync_AlreadyInstalled_ReturnsAlreadyInstalled()
+    {
+        // Arrange
+        Directory.CreateDirectory(_tempGameRoot);
+
+        // First install
+        await SubDirectoryFixerInstallerService.EnsureInstalledAsync(_tempGameRoot);
+
+        // Act - Second install
+        var result = await SubDirectoryFixerInstallerService.EnsureInstalledAsync(_tempGameRoot);
+
+        // Assert
+        Assert.Equal(SubDirectoryFixerInstallStatus.AlreadyInstalled, result.Status);
+    }
+
+    [Fact]
+    public async Task EnsureInstalledAsync_MarkerHashMismatch_UpdatesSuccessfully()
+    {
+        // Arrange
+        Directory.CreateDirectory(_tempGameRoot);
+
+        // First install
+        await SubDirectoryFixerInstallerService.EnsureInstalledAsync(_tempGameRoot);
+
+        // Tamper with marker file
+        var pluginsDir = Path.Combine(_tempGameRoot, "Plugins");
+        var markerFile = Path.Combine(pluginsDir, ".gregmodmanager-subdirfixer.sha256");
+
+        // Make sure Plugins exists in case the first call failed
+        Directory.CreateDirectory(pluginsDir);
+        await File.WriteAllTextAsync(markerFile, "invalid-hash");
+
+        // Act - Update
+        var result = await SubDirectoryFixerInstallerService.EnsureInstalledAsync(_tempGameRoot);
+
+        // Assert
+        Assert.Equal(SubDirectoryFixerInstallStatus.Installed, result.Status);
+        var newMarkerHash = await File.ReadAllTextAsync(markerFile);
+        Assert.NotEqual("invalid-hash", newMarkerHash);
+    }
+
+    [Fact]
+    public async Task EnsureInstalledAsync_FileLocked_ReturnsFailedStatus()
+    {
+        // Arrange
+        Directory.CreateDirectory(_tempGameRoot);
+
+        // Create the directory structure where it will be installed
+        var pluginsDir = Path.Combine(_tempGameRoot, "Plugins");
+        Directory.CreateDirectory(pluginsDir);
+
+        // Create a dummy file and lock it
+        var targetFile = Path.Combine(pluginsDir, "SubDirectoryFixer.dll");
+        await File.WriteAllTextAsync(targetFile, "dummy");
+
+        // Lock the file for exclusive access
+        using var stream = new FileStream(targetFile, FileMode.Open, FileAccess.ReadWrite, FileShare.None);
+
+        // Act
+        var result = await SubDirectoryFixerInstallerService.EnsureInstalledAsync(_tempGameRoot);
+
+        // Assert
+        Assert.Equal(SubDirectoryFixerInstallStatus.Failed, result.Status);
+        Assert.Contains("install failed", result.Message, StringComparison.OrdinalIgnoreCase);
+    }
+}