diff --git a/README.md b/README.md
index 960a6df..bebd0ac 100644
--- a/README.md
+++ b/README.md
@@ -100,6 +100,10 @@ Registry64 등록, 지속 K3D pin, `127.0.0.1:30001` Development Live 승인 및
 빌드를 한 번에 확인하므로 시간이 걸릴 수 있습니다. 이 과정은 DB 연결, K3D COM 활성화,
 Tornado2/PGM 연결이나 송출 명령을 실행하지 않습니다. 성공 뒤 누르는 다음 F5에서는
 `Cuts`와 `Res\MmoneyCoder.ini`를 복사하지 않고 선택한 원래 경로를 직접 사용합니다.
+기존 보호 Live 설정이 고정값과 다르면 자동으로 덮어쓰지 않고 정확한 원인과
+`기존 Live 설정 교체 후 다시 시도` 버튼을 표시합니다. 이 버튼은 안내된
+`127.0.0.1:30001`, 채널 미지정, 고정 allowlist/timeout만 명시적으로 교체하며 K3D pin이나
+기존 runtime binding은 변경하지 않습니다.
 
 K3D는 다음 회사 표준 배치만 허용합니다.
 
diff --git a/docs/DEVELOPMENT_LIVE_VISUAL_STUDIO.md b/docs/DEVELOPMENT_LIVE_VISUAL_STUDIO.md
index 28018c7..dbb23da 100644
--- a/docs/DEVELOPMENT_LIVE_VISUAL_STUDIO.md
+++ b/docs/DEVELOPMENT_LIVE_VISUAL_STUDIO.md
@@ -37,8 +37,11 @@
 
 설정 중에는 DB 연결, K3D COM 활성화, Tornado2/PGM 연결 또는 송출 명령을 실행하지 않는다.
 설정을 완료한 뒤 창을 닫고 F5를 한 번 더 누르면 검증된 전체 앱이 시작된다. 기존 로컬
-설정과 충돌하거나 K3D pin이 달라 자동 설정이 중단되면 대상을 검토한 뒤 아래 수동 교체
-절차를 사용한다. 자세한 절차는
+Live 설정과 충돌하면 화면은 자동으로 덮어쓰지 않고 `127.0.0.1:30001`, 채널 미지정,
+고정 allowlist/timeout으로 교체된다는 안내와 별도
+`기존 Live 설정 교체 후 다시 시도` 버튼을 표시한다. 이 명시적 재시도는 K3D pin과 runtime
+binding을 바꾸지 않는다. runtime binding 충돌이나 K3D pin 차이로 중단되면 대상을 검토한
+뒤 아래 수동 교체 절차를 사용한다. 자세한 절차는
 [개발 PGM 인수 절차](DEVELOPMENT_LIVE_HANDOFF.md#2-기존-자산-보유-pc-clone-후-1회-초기화)를
 따른다.
 
diff --git a/scripts/Initialize-ExistingDevelopmentPc.ps1 b/scripts/Initialize-ExistingDevelopmentPc.ps1
index cf5c865..1e50d5d 100644
--- a/scripts/Initialize-ExistingDevelopmentPc.ps1
+++ b/scripts/Initialize-ExistingDevelopmentPc.ps1
@@ -1494,7 +1494,8 @@ function Get-DevelopmentLivePreflight {
         # refused. The caller asked to configure Live, so failure is fail-closed.
         Remove-DevelopmentLiveAuthorizationFailClosed -Path $authorizationPath
         throw (
-            'Existing Development Live files differ from the exact requested ' +
+            '[MBN_SETUP_LIVE_CONFIG_REPLACEMENT_REQUIRED] Existing Development ' +
+            'Live files differ from the exact requested ' +
             'endpoint/hash contract. Re-run with -ReplaceLiveConfig.')
     }
 
diff --git a/src/MBN_STOCK_WEBVIEW.LegacyParityApp/FirstRunSetupWindow.xaml b/src/MBN_STOCK_WEBVIEW.LegacyParityApp/FirstRunSetupWindow.xaml
index 85406c0..0f650bb 100644
--- a/src/MBN_STOCK_WEBVIEW.LegacyParityApp/FirstRunSetupWindow.xaml
+++ b/src/MBN_STOCK_WEBVIEW.LegacyParityApp/FirstRunSetupWindow.xaml
@@ -104,6 +104,12 @@
                         Click="OnCloseClicked"
                         Content="닫기"
                         Visibility="Collapsed" />
+                    <Button
+                        x:Name="ReplaceLiveConfigButton"
+                        Click="OnReplaceLiveConfigClicked"
+                        Content="기존 Live 설정 교체 후 다시 시도"
+                        IsEnabled="False"
+                        Visibility="Collapsed" />
                     <Button
                         x:Name="InstallButton"
                         Click="OnInstallClicked"
diff --git a/src/MBN_STOCK_WEBVIEW.LegacyParityApp/FirstRunSetupWindow.xaml.cs b/src/MBN_STOCK_WEBVIEW.LegacyParityApp/FirstRunSetupWindow.xaml.cs
index 91f6a2b..dfc4349 100644
--- a/src/MBN_STOCK_WEBVIEW.LegacyParityApp/FirstRunSetupWindow.xaml.cs
+++ b/src/MBN_STOCK_WEBVIEW.LegacyParityApp/FirstRunSetupWindow.xaml.cs
@@ -1,5 +1,6 @@
 using System.Diagnostics;
 using System.Reflection;
+using System.Text;
 using MBN_STOCK_WEBVIEW.Infrastructure;
 using MBN_STOCK_WEBVIEW.LegacyApplication;
 using Microsoft.UI.Windowing;
@@ -14,10 +15,14 @@ public sealed partial class FirstRunSetupWindow : Window
     private const string RepositoryRootMetadataKey = "SourceRepositoryRoot";
     private const string SetupScriptRelativePath =
         @"scripts\Initialize-ExistingDevelopmentPc.ps1";
+    private const string LiveConfigReplacementRequiredMarker =
+        "MBN_SETUP_LIVE_CONFIG_REPLACEMENT_REQUIRED";
+    private const int MaximumCapturedOutputCharacters = 16 * 1024;
 
     private string? _cutsDirectory;
     private string? _resourceDirectory;
     private bool _setupRunning;
+    private bool _liveConfigReplacementAvailable;
     private readonly AppWindow _appWindow;
 
     public FirstRunSetupWindow()
@@ -36,6 +41,7 @@ public sealed partial class FirstRunSetupWindow : Window
             return;
         }
 
+        ClearLiveConfigReplacement();
         _cutsDirectory = null;
         CutsPathText.Text = "선택되지 않음";
         InstallButton.IsEnabled = false;
@@ -63,6 +69,7 @@ public sealed partial class FirstRunSetupWindow : Window
             return;
         }
 
+        ClearLiveConfigReplacement();
         _resourceDirectory = null;
         ResourcePathText.Text = "선택되지 않음";
         InstallButton.IsEnabled = false;
@@ -89,6 +96,30 @@ public sealed partial class FirstRunSetupWindow : Window
             return;
         }
 
+        ClearLiveConfigReplacement();
+        await RunSetupFromUiAsync(replaceLiveConfig: false);
+    }
+
+    private async void OnReplaceLiveConfigClicked(
+        object sender,
+        RoutedEventArgs e)
+    {
+        if (_setupRunning || !_liveConfigReplacementAvailable)
+        {
+            return;
+        }
+
+        ClearLiveConfigReplacement();
+        await RunSetupFromUiAsync(replaceLiveConfig: true);
+    }
+
+    private async Task RunSetupFromUiAsync(bool replaceLiveConfig)
+    {
+        if (_setupRunning)
+        {
+            return;
+        }
+
         if (!TryResolveRuntimeRoot(
                 _cutsDirectory,
                 _resourceDirectory,
@@ -123,8 +154,10 @@ public sealed partial class FirstRunSetupWindow : Window
                 repositoryRoot,
                 runtimeRoot!,
                 _cutsDirectory!,
-                _resourceDirectory!);
+                _resourceDirectory!,
+                replaceLiveConfig);
 
+            ClearLiveConfigReplacement();
             SetupStatusBar.Title = "설정 완료";
             SetupStatusBar.Message =
                 "Cuts/Res, DB, K3D 및 Live 설정을 검증했습니다. 이 창을 닫고 Visual Studio에서 F5를 한 번 더 누르세요.";
@@ -132,10 +165,21 @@ public sealed partial class FirstRunSetupWindow : Window
             InstallButton.Visibility = Visibility.Collapsed;
             CloseButton.Visibility = Visibility.Visible;
         }
+        catch (VerifiedSetupException exception)
+        {
+            _liveConfigReplacementAvailable =
+                exception.LiveConfigReplacementAvailable;
+            ReplaceLiveConfigButton.Visibility =
+                _liveConfigReplacementAvailable
+                    ? Visibility.Visible
+                    : Visibility.Collapsed;
+            ShowError(exception.Message);
+        }
         catch
         {
+            ClearLiveConfigReplacement();
             ShowError(
-                "개발 PC 자동 설정에 실패했습니다. Res\\MmoneyCoder.ini, C:\\K3DAsyncEngine x64 등록, Tornado2의 127.0.0.1:30001 설정을 확인해 주세요.");
+                "개발 PC 자동 설정에 실패했습니다. 선택한 Res\\MmoneyCoder.ini, C:\\K3DAsyncEngine x64 등록과 Debug x64 빌드 환경을 확인해 주세요.");
         }
         finally
         {
@@ -317,7 +361,8 @@ public sealed partial class FirstRunSetupWindow : Window
         string repositoryRoot,
         string runtimeRoot,
         string cutsDirectory,
-        string resourceDirectory)
+        string resourceDirectory,
+        bool replaceLiveConfig)
     {
         var powershellPath = Path.Combine(
             Environment.GetFolderPath(Environment.SpecialFolder.System),
@@ -360,6 +405,10 @@ public sealed partial class FirstRunSetupWindow : Window
         AddArgument("-PlayoutPort");
         AddArgument("30001");
         AddArgument("-PinRegisteredK3D");
+        if (replaceLiveConfig)
+        {
+            AddArgument("-ReplaceLiveConfig");
+        }
 
         using var process = new Process
         {
@@ -371,14 +420,16 @@ public sealed partial class FirstRunSetupWindow : Window
                 "The verified development-PC initializer could not be started.");
         }
 
-        var standardOutput = DrainOutputAsync(process.StandardOutput);
-        var standardError = DrainOutputAsync(process.StandardError);
+        var standardOutput = CaptureOutputTailAsync(process.StandardOutput);
+        var standardError = CaptureOutputTailAsync(process.StandardError);
         await process.WaitForExitAsync();
         await Task.WhenAll(standardOutput, standardError);
         if (process.ExitCode != 0)
         {
-            throw new InvalidOperationException(
-                $"The verified development-PC initializer failed with exit code {process.ExitCode}.");
+            throw CreateVerifiedSetupException(
+                process.ExitCode,
+                standardOutput.Result,
+                standardError.Result);
         }
 
         var loaded = new LegacyOperatorSettingsStore().Load();
@@ -420,12 +471,63 @@ public sealed partial class FirstRunSetupWindow : Window
         void AddArgument(string value) => startInfo.ArgumentList.Add(value);
     }
 
-    private static async Task DrainOutputAsync(StreamReader reader)
+    private static async Task<string> CaptureOutputTailAsync(StreamReader reader)
     {
+        var captured = new StringBuilder(MaximumCapturedOutputCharacters);
         var buffer = new char[4096];
-        while (await reader.ReadAsync(buffer.AsMemory()) > 0)
+        int charactersRead;
+        while ((charactersRead = await reader.ReadAsync(buffer.AsMemory())) > 0)
         {
+            captured.Append(buffer, 0, charactersRead);
+            var excess = captured.Length - MaximumCapturedOutputCharacters;
+            if (excess > 0)
+            {
+                captured.Remove(0, excess);
+            }
         }
+
+        return captured.ToString();
+    }
+
+    private static VerifiedSetupException CreateVerifiedSetupException(
+        int exitCode,
+        string standardOutput,
+        string standardError)
+    {
+        var diagnostic = string.Concat(
+            standardError,
+            Environment.NewLine,
+            standardOutput);
+        if (diagnostic.Contains(
+                LiveConfigReplacementRequiredMarker,
+                StringComparison.Ordinal))
+        {
+            return new VerifiedSetupException(
+                "기존 보호 송출 설정이 현재 개발 PC 고정값과 다릅니다. 아래 버튼을 누르면 playout.local.json을 127.0.0.1:30001, 채널 미지정, 고정 허용 목록/시간 제한으로 교체하고 1회 승인을 새로 발급합니다. K3D pin은 변경하지 않습니다.",
+                liveConfigReplacementAvailable: true);
+        }
+
+        if (diagnostic.Contains(
+                "Re-run with -ReplaceRuntimeBinding.",
+                StringComparison.Ordinal))
+        {
+            return new VerifiedSetupException(
+                "이 PC에 저장된 Cuts/Res 또는 빌드 경로가 방금 선택한 폴더와 다릅니다. 기존 로컬 경로 설정을 확인한 뒤 다시 진행해 주세요.",
+                liveConfigReplacementAvailable: false);
+        }
+
+        if (diagnostic.Contains(
+                "Automatic pinning cannot approve a changed DLL.",
+                StringComparison.Ordinal))
+        {
+            return new VerifiedSetupException(
+                "등록된 K3D 파일의 해시가 이 PC의 기존 pin과 다릅니다. K3D 설치 파일을 독립적으로 확인하기 전에는 설정을 계속할 수 없습니다.",
+                liveConfigReplacementAvailable: false);
+        }
+
+        return new VerifiedSetupException(
+            $"개발 PC 검증 도구가 종료 코드 {exitCode}로 중단되었습니다. 선택한 Res, K3D 등록과 Debug x64 빌드 출력을 확인해 주세요.",
+            liveConfigReplacementAvailable: false);
     }
 
     private static void EnsureOrdinaryFile(string path, string message)
@@ -455,6 +557,8 @@ public sealed partial class FirstRunSetupWindow : Window
         _setupRunning = running;
         ChooseCutsButton.IsEnabled = !running;
         ChooseResourceButton.IsEnabled = !running;
+        ReplaceLiveConfigButton.IsEnabled =
+            !running && _liveConfigReplacementAvailable;
         InstallButton.IsEnabled = !running &&
             _cutsDirectory is not null &&
             _resourceDirectory is not null;
@@ -463,6 +567,13 @@ public sealed partial class FirstRunSetupWindow : Window
             : Visibility.Collapsed;
     }
 
+    private void ClearLiveConfigReplacement()
+    {
+        _liveConfigReplacementAvailable = false;
+        ReplaceLiveConfigButton.IsEnabled = false;
+        ReplaceLiveConfigButton.Visibility = Visibility.Collapsed;
+    }
+
     private void ShowWarning(string message)
     {
         SetupStatusBar.Title = "확인 필요";
@@ -484,4 +595,18 @@ public sealed partial class FirstRunSetupWindow : Window
         return AppWindow.GetFromWindowId(windowId);
     }
 
+    private sealed class VerifiedSetupException : InvalidOperationException
+    {
+        public VerifiedSetupException(
+            string message,
+            bool liveConfigReplacementAvailable)
+            : base(message)
+        {
+            LiveConfigReplacementAvailable =
+                liveConfigReplacementAvailable;
+        }
+
+        public bool LiveConfigReplacementAvailable { get; }
+    }
+
 }
diff --git a/tests/MBN_STOCK_WEBVIEW.LegacyWeb.Tests/LegacyFirstRunSetupNativeContractTests.cs b/tests/MBN_STOCK_WEBVIEW.LegacyWeb.Tests/LegacyFirstRunSetupNativeContractTests.cs
index 604b120..ad17ee0 100644
--- a/tests/MBN_STOCK_WEBVIEW.LegacyWeb.Tests/LegacyFirstRunSetupNativeContractTests.cs
+++ b/tests/MBN_STOCK_WEBVIEW.LegacyWeb.Tests/LegacyFirstRunSetupNativeContractTests.cs
@@ -63,6 +63,7 @@ public sealed class LegacyFirstRunSetupNativeContractTests
 
         Assert.Contains("Cuts 폴더 선택", buttons);
         Assert.Contains("Res 폴더 선택", buttons);
+        Assert.Contains("기존 Live 설정 교체 후 다시 시도", buttons);
         Assert.DoesNotContain("INI 파일 선택", source, StringComparison.Ordinal);
         Assert.DoesNotContain("비밀번호", source, StringComparison.Ordinal);
         Assert.DoesNotContain("포트 입력", source, StringComparison.Ordinal);
@@ -124,6 +125,10 @@ public sealed class LegacyFirstRunSetupNativeContractTests
         var setup = File.ReadAllText(Path.Combine(
             AppRoot,
             "FirstRunSetupWindow.xaml.cs"));
+        var initializer = File.ReadAllText(Path.Combine(
+            RepositoryRoot,
+            "scripts",
+            "Initialize-ExistingDevelopmentPc.ps1"));
 
         Assert.Contains(
             "await RunVerifiedSetupAsync(",
@@ -178,13 +183,49 @@ public sealed class LegacyFirstRunSetupNativeContractTests
             setup,
             StringComparison.Ordinal);
         Assert.Contains(
-            "DrainOutputAsync(process.StandardOutput)",
+            "if (replaceLiveConfig)",
             setup,
             StringComparison.Ordinal);
         Assert.Contains(
-            "DrainOutputAsync(process.StandardError)",
+            "AddArgument(\"-ReplaceLiveConfig\")",
             setup,
             StringComparison.Ordinal);
+        Assert.DoesNotContain(
+            "AddArgument(\"-ReplaceRuntimeBinding\")",
+            setup,
+            StringComparison.Ordinal);
+        Assert.DoesNotContain(
+            "AddArgument(\"-ReplaceK3DPin\")",
+            setup,
+            StringComparison.Ordinal);
+        Assert.Contains(
+            "CaptureOutputTailAsync(process.StandardOutput)",
+            setup,
+            StringComparison.Ordinal);
+        Assert.Contains(
+            "CaptureOutputTailAsync(process.StandardError)",
+            setup,
+            StringComparison.Ordinal);
+        Assert.Contains(
+            "MaximumCapturedOutputCharacters = 16 * 1024",
+            setup,
+            StringComparison.Ordinal);
+        Assert.Contains(
+            "RunSetupFromUiAsync(replaceLiveConfig: false)",
+            setup,
+            StringComparison.Ordinal);
+        Assert.Contains(
+            "RunSetupFromUiAsync(replaceLiveConfig: true)",
+            setup,
+            StringComparison.Ordinal);
+        Assert.Contains(
+            "MBN_SETUP_LIVE_CONFIG_REPLACEMENT_REQUIRED",
+            setup,
+            StringComparison.Ordinal);
+        Assert.Contains(
+            "[MBN_SETUP_LIVE_CONFIG_REPLACEMENT_REQUIRED]",
+            initializer,
+            StringComparison.Ordinal);
         Assert.Contains(
             "loaded.Settings.SceneDirectory",
             setup,
diff --git a/tests/MBN_STOCK_WEBVIEW.LegacyWeb.Tests/LegacyRuntimeAssetDeploymentContractTests.cs b/tests/MBN_STOCK_WEBVIEW.LegacyWeb.Tests/LegacyRuntimeAssetDeploymentContractTests.cs
index 600fcbe..0e112ee 100644
--- a/tests/MBN_STOCK_WEBVIEW.LegacyWeb.Tests/LegacyRuntimeAssetDeploymentContractTests.cs
+++ b/tests/MBN_STOCK_WEBVIEW.LegacyWeb.Tests/LegacyRuntimeAssetDeploymentContractTests.cs
@@ -851,7 +851,7 @@ public sealed class LegacyRuntimeAssetDeploymentContractTests
             initializer,
             StringComparison.Ordinal);
         Assert.Contains(
-            "Existing Development Live files differ from the exact requested",
+            "[MBN_SETUP_LIVE_CONFIG_REPLACEMENT_REQUIRED]",
             initializer,
             StringComparison.Ordinal);