diff --git a/VideoDownloader.App/AppPaths.cs b/VideoDownloader.App/AppPaths.cs
new file mode 100644
index 0000000..aaf14f1
--- /dev/null
+++ b/VideoDownloader.App/AppPaths.cs
@@ -0,0 +1,14 @@
+namespace VideoDownloader.App;
+
+/// <summary>
+/// 앱 데이터 디렉터리 결정. 기본 %AppData%/VideoDownloader.
+/// 환경변수 VD_DATA_DIR 로 오버라이드 — E2E 테스트가 실사용자 프로필/설정/세션과
+/// 격리된 임시 디렉터리에서 실행되도록 한다(결정적 테스트를 위한 공식 후크).
+/// </summary>
+public static class AppPaths
+{
+    public static string DataDir =>
+        Environment.GetEnvironmentVariable("VD_DATA_DIR") is { Length: > 0 } env
+            ? env
+            : Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "VideoDownloader");
+}
diff --git a/VideoDownloader.App/Browser/BrowserStore.cs b/VideoDownloader.App/Browser/BrowserStore.cs
index 37bc140..159dfd2 100644
--- a/VideoDownloader.App/Browser/BrowserStore.cs
+++ b/VideoDownloader.App/Browser/BrowserStore.cs
@@ -7,8 +7,7 @@ namespace VideoDownloader.App.Browser;
 ///    손상 파일은 백업 후 빈 목록을 반환(다음 저장이 원본을 덮어쓰는 데이터 손실 방지).</summary>
 public static class BrowserStore
 {
-    private static string Dir => Path.Combine(
-        Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "VideoDownloader");
+    private static string Dir => AppPaths.DataDir;
     private static string BookmarksPath => Path.Combine(Dir, "bookmarks.json");
     private static string HistoryPath => Path.Combine(Dir, "history.json");
     private static readonly JsonSerializerOptions JsonOpts = new() { WriteIndented = true };
diff --git a/VideoDownloader.App/Core/ConfigStore.cs b/VideoDownloader.App/Core/ConfigStore.cs
index f5f0ec3..d9ad23b 100644
--- a/VideoDownloader.App/Core/ConfigStore.cs
+++ b/VideoDownloader.App/Core/ConfigStore.cs
@@ -6,8 +6,7 @@ namespace VideoDownloader.App.Core;
 /// <summary>%AppData%/VideoDownloader/config.json 으로 설정 영속화</summary>
 public static class ConfigStore
 {
-    private static string Dir => Path.Combine(
-        Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "VideoDownloader");
+    private static string Dir => AppPaths.DataDir;
     private static string FilePath => Path.Combine(Dir, "config.json");
 
     private static readonly JsonSerializerOptions JsonOpts = new() { WriteIndented = true };
diff --git a/VideoDownloader.App/MainWindow.xaml.cs b/VideoDownloader.App/MainWindow.xaml.cs
index 2c0c9bf..1f302d0 100644
--- a/VideoDownloader.App/MainWindow.xaml.cs
+++ b/VideoDownloader.App/MainWindow.xaml.cs
@@ -145,9 +145,8 @@ public partial class MainWindow : Window
     [DllImport("dwmapi.dll")]
     private static extern int DwmSetWindowAttribute(IntPtr hwnd, int attribute, ref int pvAttribute, int cbAttribute);
 
-    /// <summary>WebView2 영속 프로필 경로. 쿠키·세션·localStorage·캐시가 여기 보존되어 앱/빌드 재시작에도 유지.</summary>
-    internal static string AppDataDir => Path.Combine(
-        Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "VideoDownloader");
+    /// <summary>앱 데이터 디렉터리(AppPaths.DataDir — VD_DATA_DIR 오버라이드 지원).</summary>
+    internal static string AppDataDir => AppPaths.DataDir;
 
     internal static string ProfileFolder => Path.Combine(AppDataDir, "webview");
 
diff --git a/VideoDownloader.Tests/E2E/MainWindowSmokeE2ETests.cs b/VideoDownloader.Tests/E2E/MainWindowSmokeE2ETests.cs
index 324ab17..1a31466 100644
--- a/VideoDownloader.Tests/E2E/MainWindowSmokeE2ETests.cs
+++ b/VideoDownloader.Tests/E2E/MainWindowSmokeE2ETests.cs
@@ -14,6 +14,11 @@ public class MainWindowSmokeE2ETests
     [Fact]
     public async Task MainWindow_기동_탐색_탭전환_닫기_복원_검색바_전체화면_E2E()
     {
+        // VD_DATA_DIR 격리: 실사용자 설정/세션/프로필과 분리된 임시 데이터 디렉터리 (결정적 테스트)
+        var dataDir = Path.Combine(Path.GetTempPath(), $"vd_e2e_data_{Guid.NewGuid():N}");
+        Environment.SetEnvironmentVariable("VD_DATA_DIR", dataDir);
+        try
+        {
         using var sta = StaDispatcher.Start();
         WpfTestApp.Ensure(sta.Dispatcher);
         var ok = await sta.InvokeAsync(async () =>
@@ -77,6 +82,12 @@ public class MainWindowSmokeE2ETests
         Assert.True(ok.findCollapsed, "검색 바 미닫힘");
         Assert.True(ok.toolbarHidden, "전체화면에서 크롬 미숨김");
         Assert.True(ok.toolbarBack, "전체화면 복원 실패");
+        }
+        finally
+        {
+            Environment.SetEnvironmentVariable("VD_DATA_DIR", null);
+            try { Directory.Delete(dataDir, true); } catch { }
+        }
     }
 
     private static Task WaitUntilNavCompleted(Microsoft.Web.WebView2.Core.CoreWebView2 cv)