diff --git a/src/Filee.Engines/Infrastructure/EngineInstaller.cs b/src/Filee.Engines/Infrastructure/EngineInstaller.cs
index ae69a1790..037d482be 100644
--- a/src/Filee.Engines/Infrastructure/EngineInstaller.cs
+++ b/src/Filee.Engines/Infrastructure/EngineInstaller.cs
@@ -386,10 +386,29 @@ private async Task UnpackAsync(EngineComponent component, string file, Cancellat
         finally
         {
             if (Directory.Exists(staging))
-                Directory.Delete(staging, recursive: true);
+                DeleteStagingDirectory(staging);
         }
     }
 
+    /// <summary>
+    /// Removes read-only attributes before deleting an unpacking folder. Administrative MSI extraction preserves
+    /// Windows file attributes; Calibre includes read-only DLLs (e.g. amatch.dll), which make recursive deletion fail.
+    /// </summary>
+    internal static void DeleteStagingDirectory(string folder)
+    {
+        if (OperatingSystem.IsWindows())
+        {
+            foreach (var file in Directory.EnumerateFiles(folder, "*", SearchOption.AllDirectories))
+            {
+                var attributes = File.GetAttributes(file);
+                if ((attributes & FileAttributes.ReadOnly) != 0)
+                    File.SetAttributes(file, attributes & ~FileAttributes.ReadOnly);
+            }
+        }
+
+        Directory.Delete(folder, recursive: true);
+    }
+
     internal static async Task UnpackTarAsync(string file, string target, string kind, CancellationToken cancellationToken)
     {
         Directory.CreateDirectory(target);
diff --git a/tests/Filee.Engines.Tests/EngineInstallerTests.cs b/tests/Filee.Engines.Tests/EngineInstallerTests.cs
index 33f81084c..a28115b2e 100644
--- a/tests/Filee.Engines.Tests/EngineInstallerTests.cs
+++ b/tests/Filee.Engines.Tests/EngineInstallerTests.cs
@@ -403,6 +403,22 @@ public async Task LibreOffice_extensions_go_into_the_installed_LibreOffice_and_n
         Assert.True(installer.IsInstalled(package));
     }
 
+    [Fact]
+    public void Staging_cleanup_removes_read_only_MSI_files_on_Windows()
+    {
+        Assert.SkipUnless(OperatingSystem.IsWindows(), "Windows MSI packages preserve read-only file attributes.");
+
+        var staging = Path.Combine(_root, "~staging");
+        Directory.CreateDirectory(Path.Combine(staging, "Program", "bin"));
+        var dll = Path.Combine(staging, "Program", "bin", "amatch.dll");
+        File.WriteAllText(dll, "MSI payload");
+        File.SetAttributes(dll, File.GetAttributes(dll) | FileAttributes.ReadOnly);
+
+        EngineInstaller.DeleteStagingDirectory(staging);
+
+        Assert.False(Directory.Exists(staging));
+    }
+
     [Fact]
     public void LibreOffice_is_trimmed_to_what_headless_conversion_needs()
     {