diff --git a/src/renderer/inbox/components/settings/AutostartSection.tsx b/src/renderer/inbox/components/settings/AutostartSection.tsx
index b7c9384..9e27e4e 100644
--- a/src/renderer/inbox/components/settings/AutostartSection.tsx
+++ b/src/renderer/inbox/components/settings/AutostartSection.tsx
@@ -4,6 +4,7 @@ import { inboxApi } from '../../api.js';
 
 export function AutostartSection(): React.ReactElement {
   const [data, setData] = useState<AutostartResponse | null>(null);
+  const [expanded, setExpanded] = useState(false);
 
   useEffect(() => {
     void (async () => {
@@ -21,12 +22,58 @@ export function AutostartSection(): React.ReactElement {
     return <div style={{ fontSize: 12, color: '#666' }}>로딩 중...</div>;
   }
 
+  const d = data.diagnostic;
+  // v0.2.7 F12 deeper fix — withArgs vs noArgs 의 openAtLogin 불일치, 또는
+  // executableWillLaunchAtLogin = false 면 mismatch 로 간주 (등록은 됐지만 실제론
+  // 로그인 시 실행되지 않을 수 있는 상태).
+  const mismatch = d.withArgs.openAtLogin !== d.noArgs.openAtLogin
+    || (data.openAtLogin && !d.withArgs.executableWillLaunchAtLogin);
+
   return (
     <div>
       <label style={{ display: 'flex', gap: 8, alignItems: 'center', fontSize: 13 }}>
         <input type="checkbox" checked={data.openAtLogin} onChange={onToggle} />
         앱 시작 시 자동으로 실행
       </label>
+      {mismatch && (
+        <div style={{ color: '#c33', fontSize: 12, marginTop: 4 }}>
+          ⚠️ 등록 상태 불일치 감지 — 진단 정보 확인 후 재등록을 시도하세요.
+        </div>
+      )}
+      <button
+        onClick={() => setExpanded(!expanded)}
+        style={{
+          background: 'none',
+          border: 'none',
+          cursor: 'pointer',
+          fontSize: 12,
+          color: '#0a4b80',
+          marginTop: 4,
+          padding: 0
+        }}
+      >
+        {expanded ? '▾' : '▸'} 진단 정보
+      </button>
+      {expanded && (
+        <div
+          style={{
+            fontSize: 11,
+            lineHeight: 1.6,
+            marginTop: 4,
+            fontFamily: 'monospace',
+            background: '#f5f5f5',
+            padding: 8,
+            borderRadius: 4,
+            wordBreak: 'break-all'
+          }}
+        >
+          <div>표준 (--hidden 인자): openAtLogin={String(d.withArgs.openAtLogin)}, willLaunch={String(d.withArgs.executableWillLaunchAtLogin)}</div>
+          <div>비교 (인자 없이): openAtLogin={String(d.noArgs.openAtLogin)}, willLaunch={String(d.noArgs.executableWillLaunchAtLogin)}</div>
+          <div>실행 파일 경로: {d.execPath}</div>
+          {d.registryPath !== undefined && <div>registry 경로: {d.registryPath}</div>}
+          {d.registryValue !== undefined && <div>registry 값: {d.registryValue ?? '(없음)'}</div>}
+        </div>
+      )}
     </div>
   );
 }
diff --git a/tests/unit/AutostartSection.test.tsx b/tests/unit/AutostartSection.test.tsx
index 78c2429..234143b 100644
--- a/tests/unit/AutostartSection.test.tsx
+++ b/tests/unit/AutostartSection.test.tsx
@@ -43,4 +43,57 @@ describe('AutostartSection', () => {
     fireEvent.click(toggle);
     await waitFor(() => expect(inboxApi.setAutostart).toHaveBeenCalledWith(false));
   });
+
+  it('renders diagnostic panel when expanded, shows mismatch warning + execPath', async () => {
+    const { inboxApi } = await import('../../src/renderer/inbox/api.js');
+    vi.mocked(inboxApi.getAutostart).mockResolvedValueOnce({
+      openAtLogin: true,
+      diagnostic: {
+        withArgs: { openAtLogin: true, executableWillLaunchAtLogin: true },
+        noArgs: { openAtLogin: false, executableWillLaunchAtLogin: true },
+        execPath: '/path/to/Inkling.exe'
+      }
+    });
+    render(<AutostartSection />);
+    await screen.findByRole('checkbox');
+    fireEvent.click(screen.getByRole('button', { name: /진단 정보/ }));
+    expect(await screen.findByText(/⚠️/)).toBeInTheDocument();
+    expect(screen.getByText(/path\/to\/Inkling\.exe/)).toBeInTheDocument();
+    expect(screen.getByText(/표준 \(--hidden 인자\)/)).toBeInTheDocument();
+    expect(screen.getByText(/비교 \(인자 없이\)/)).toBeInTheDocument();
+  });
+
+  it('shows registry info when present (Win)', async () => {
+    const { inboxApi } = await import('../../src/renderer/inbox/api.js');
+    vi.mocked(inboxApi.getAutostart).mockResolvedValueOnce({
+      openAtLogin: true,
+      diagnostic: {
+        withArgs: { openAtLogin: true, executableWillLaunchAtLogin: true },
+        noArgs: { openAtLogin: true, executableWillLaunchAtLogin: true },
+        execPath: 'C:\\app.exe',
+        registryPath: 'HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Run\\Inkling',
+        registryValue: '"C:\\app.exe" --hidden'
+      }
+    });
+    render(<AutostartSection />);
+    await screen.findByRole('checkbox');
+    fireEvent.click(screen.getByRole('button', { name: /진단 정보/ }));
+    expect(screen.getByText(/registry 경로/)).toBeInTheDocument();
+    expect(screen.getByText(/registry 값/)).toBeInTheDocument();
+  });
+
+  it('no mismatch warning when withArgs == noArgs and willLaunch=true', async () => {
+    const { inboxApi } = await import('../../src/renderer/inbox/api.js');
+    vi.mocked(inboxApi.getAutostart).mockResolvedValueOnce({
+      openAtLogin: true,
+      diagnostic: {
+        withArgs: { openAtLogin: true, executableWillLaunchAtLogin: true },
+        noArgs: { openAtLogin: true, executableWillLaunchAtLogin: true },
+        execPath: '/p'
+      }
+    });
+    render(<AutostartSection />);
+    await screen.findByRole('checkbox');
+    expect(screen.queryByText(/⚠️/)).not.toBeInTheDocument();
+  });
 });