diff --git a/.editorconfig b/.editorconfig
index 8b93976..3c1a03b 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -146,6 +146,11 @@ dotnet_diagnostic.IDE0044.severity = warning
 
 # CSharp code style settings:
 [*.cs]
+
+# Require file header OR A source file contains a header that does not match the required text
+file_header_template = This file is subject to the terms and conditions defined\nin file 'LICENSE', which is part of this source code package.
+dotnet_diagnostic.IDE0073.severity = error
+
 # Newline settings
 csharp_new_line_before_open_brace = all
 csharp_new_line_before_else = true
diff --git a/DepotDownloader/AccountSettingsStore.cs b/DepotDownloader/AccountSettingsStore.cs
index 2374a92..7e1594b 100644
--- a/DepotDownloader/AccountSettingsStore.cs
+++ b/DepotDownloader/AccountSettingsStore.cs
@@ -1,3 +1,6 @@
+// This file is subject to the terms and conditions defined
+// in file 'LICENSE', which is part of this source code package.
+
 using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
diff --git a/DepotDownloader/Ansi.cs b/DepotDownloader/Ansi.cs
index 7041deb..b17b597 100644
--- a/DepotDownloader/Ansi.cs
+++ b/DepotDownloader/Ansi.cs
@@ -1,3 +1,6 @@
+// This file is subject to the terms and conditions defined
+// in file 'LICENSE', which is part of this source code package.
+
 using System;
 using Spectre.Console;
 
diff --git a/DepotDownloader/CDNClientPool.cs b/DepotDownloader/CDNClientPool.cs
index 2ed0a08..596beea 100644
--- a/DepotDownloader/CDNClientPool.cs
+++ b/DepotDownloader/CDNClientPool.cs
@@ -1,3 +1,6 @@
+// This file is subject to the terms and conditions defined
+// in file 'LICENSE', which is part of this source code package.
+
 using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
diff --git a/DepotDownloader/ContentDownloader.cs b/DepotDownloader/ContentDownloader.cs
index fa97b98..9042c39 100644
--- a/DepotDownloader/ContentDownloader.cs
+++ b/DepotDownloader/ContentDownloader.cs
@@ -1,3 +1,6 @@
+// This file is subject to the terms and conditions defined
+// in file 'LICENSE', which is part of this source code package.
+
 using System;
 using System.Buffers;
 using System.Collections.Concurrent;
diff --git a/DepotDownloader/DepotConfigStore.cs b/DepotDownloader/DepotConfigStore.cs
index 99f052c..15e1539 100644
--- a/DepotDownloader/DepotConfigStore.cs
+++ b/DepotDownloader/DepotConfigStore.cs
@@ -1,3 +1,6 @@
+// This file is subject to the terms and conditions defined
+// in file 'LICENSE', which is part of this source code package.
+
 using System;
 using System.Collections.Generic;
 using System.IO;
diff --git a/DepotDownloader/DownloadConfig.cs b/DepotDownloader/DownloadConfig.cs
index 1022aac..97f2bad 100644
--- a/DepotDownloader/DownloadConfig.cs
+++ b/DepotDownloader/DownloadConfig.cs
@@ -1,4 +1,7 @@
-using System.Collections.Generic;
+// This file is subject to the terms and conditions defined
+// in file 'LICENSE', which is part of this source code package.
+
+using System.Collections.Generic;
 using System.Text.RegularExpressions;
 
 namespace DepotDownloader
diff --git a/DepotDownloader/HttpClientFactory.cs b/DepotDownloader/HttpClientFactory.cs
index aa642bc..7a62211 100644
--- a/DepotDownloader/HttpClientFactory.cs
+++ b/DepotDownloader/HttpClientFactory.cs
@@ -1,3 +1,6 @@
+// This file is subject to the terms and conditions defined
+// in file 'LICENSE', which is part of this source code package.
+
 using System.IO;
 using System.Net.Http;
 using System.Net.Http.Headers;
diff --git a/DepotDownloader/HttpDiagnosticEventListener.cs b/DepotDownloader/HttpDiagnosticEventListener.cs
index f3b1142..2602656 100644
--- a/DepotDownloader/HttpDiagnosticEventListener.cs
+++ b/DepotDownloader/HttpDiagnosticEventListener.cs
@@ -1,3 +1,6 @@
+// This file is subject to the terms and conditions defined
+// in file 'LICENSE', which is part of this source code package.
+
 using System;
 using System.Diagnostics.Tracing;
 using System.Text;
diff --git a/DepotDownloader/PlatformUtilities.cs b/DepotDownloader/PlatformUtilities.cs
index a4f0b80..2386eae 100644
--- a/DepotDownloader/PlatformUtilities.cs
+++ b/DepotDownloader/PlatformUtilities.cs
@@ -1,3 +1,6 @@
+// This file is subject to the terms and conditions defined
+// in file 'LICENSE', which is part of this source code package.
+
 using System;
 using System.Runtime.InteropServices;
 
diff --git a/DepotDownloader/Program.cs b/DepotDownloader/Program.cs
index 5221326..058654c 100644
--- a/DepotDownloader/Program.cs
+++ b/DepotDownloader/Program.cs
@@ -1,3 +1,6 @@
+// This file is subject to the terms and conditions defined
+// in file 'LICENSE', which is part of this source code package.
+
 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
diff --git a/DepotDownloader/ProtoManifest.cs b/DepotDownloader/ProtoManifest.cs
index ccc6165..b6eb010 100644
--- a/DepotDownloader/ProtoManifest.cs
+++ b/DepotDownloader/ProtoManifest.cs
@@ -1,3 +1,6 @@
+// This file is subject to the terms and conditions defined
+// in file 'LICENSE', which is part of this source code package.
+
 using System;
 using System.Collections.Generic;
 using System.IO;
diff --git a/DepotDownloader/Steam3Session.cs b/DepotDownloader/Steam3Session.cs
index 9262063..906b309 100644
--- a/DepotDownloader/Steam3Session.cs
+++ b/DepotDownloader/Steam3Session.cs
@@ -1,3 +1,6 @@
+// This file is subject to the terms and conditions defined
+// in file 'LICENSE', which is part of this source code package.
+
 using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
diff --git a/DepotDownloader/Util.cs b/DepotDownloader/Util.cs
index e53c272..46045ae 100644
--- a/DepotDownloader/Util.cs
+++ b/DepotDownloader/Util.cs
@@ -1,3 +1,6 @@
+// This file is subject to the terms and conditions defined
+// in file 'LICENSE', which is part of this source code package.
+
 using System;
 using System.Collections.Generic;
 using System.IO;