diff --git a/CompactGUI.Core.Tests/CompactGUI.Core.Tests.csproj b/CompactGUI.Core.Tests/CompactGUI.Core.Tests.csproj
new file mode 100644
index 0000000..2366154
--- /dev/null
+++ b/CompactGUI.Core.Tests/CompactGUI.Core.Tests.csproj
@@ -0,0 +1,26 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net9.0-windows</TargetFramework>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.1.0" />
+    <PackageReference Include="xunit" Version="2.4.1" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3">
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      <PrivateAssets>all</PrivateAssets>
+    </PackageReference>
+    <PackageReference Include="coverlet.collector" Version="3.1.2">
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      <PrivateAssets>all</PrivateAssets>
+    </PackageReference>
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\CompactGUI.Core\CompactGUI.Core.csproj" />
+  </ItemGroup>
+
+</Project>
diff --git a/CompactGUI.Core.Tests/CompactorTests.cs b/CompactGUI.Core.Tests/CompactorTests.cs
new file mode 100644
index 0000000..0332a5f
--- /dev/null
+++ b/CompactGUI.Core.Tests/CompactorTests.cs
@@ -0,0 +1,38 @@
+using Xunit;
+using CompactGUI.Core;
+using System.IO;
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace CompactGUI.Core.Tests
+{
+    public class CompactorTests
+    {
+        [Fact]
+        public async Task BuildWorkingFilesList_WithExclusion_ShouldExcludeCorrectFiles()
+        {
+            // Arrange
+            var tempDir = Path.Combine(Path.GetTempPath(), Path.GetRandomFileName());
+            Directory.CreateDirectory(tempDir);
+            var file1 = Path.Combine(tempDir, "test.txt");
+            var file2 = Path.Combine(tempDir, "test.log");
+            File.WriteAllText(file1, "This is a test file.");
+            File.WriteAllText(file2, "This is a log file.");
+
+            var analyser = new Analyser(tempDir, null);
+            var compactor = new Compactor(tempDir, WOFCompressionAlgorithm.XPRESS4K, new[] { ".log" }, analyser, null);
+
+            // Act
+            var fileDetails = (FileDetails)await compactor.BuildWorkingFilesList();
+            var workingFiles = new List<FileDetails>(fileDetails);
+
+            // Assert
+            Assert.Single(workingFiles);
+            Assert.Equal(file1, workingFiles[0].FileName);
+
+            // Clean up
+            Directory.Delete(tempDir, true);
+        }
+    }
+}
diff --git a/CompactGUI.Core/Compactor.cs b/CompactGUI.Core/Compactor.cs
index 0c6071f..d14627d 100644
--- a/CompactGUI.Core/Compactor.cs
+++ b/CompactGUI.Core/Compactor.cs
@@ -132,7 +132,7 @@ public async Task<IEnumerable<FileDetails>> BuildWorkingFilesList()
             .Where(fl =>
                 fl.CompressionMode != wofCompressionAlgorithm
                 && fl.UncompressedSize > clusterSize
-                && ((fl.FileInfo != null && !excludedFileExtensions.Contains(fl.FileInfo.Extension)) || excludedFileExtensions.Contains(fl.FileName))
+                && fl.FileInfo != null && !excludedFileExtensions.Contains(fl.FileInfo.Extension)
             )
             .Select(fl => new FileDetails(fl.FileName, fl.UncompressedSize))
             .ToList();