diff --git a/visual_workflow_builder/backend/api/screen_capture.py b/visual_workflow_builder/backend/api/screen_capture.py
index af86e6f7f..780be3b16 100644
--- a/visual_workflow_builder/backend/api/screen_capture.py
+++ b/visual_workflow_builder/backend/api/screen_capture.py
@@ -136,20 +136,23 @@ def capture_windows():
     project_root = Path(os.path.dirname(os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))))
     live_dir = project_root / "data" / "training" / "live_sessions"
 
-    # Trouver la session la plus récente
-    sessions = sorted(live_dir.glob("sess_*/shots"), key=lambda p: p.parent.name, reverse=True)
-    if not sessions:
-        return jsonify({'error': 'Aucune session Windows trouvée'}), 404
+    # Chercher aussi dans les sous-dossiers machine (multi-machine)
+    import time as _time
 
-    # Chercher le screenshot plein écran le plus récent (full ou heartbeat, pas les crops)
-    latest_shot = None
-    for session_shots in sessions[:3]:
-        shots = [s for s in session_shots.glob("*.png")
-                 if "full" in s.name or "heartbeat" in s.name or "focus" in s.name]
-        if shots:
-            shots.sort(key=lambda p: p.stat().st_mtime, reverse=True)
-            latest_shot = shots[0]
-            break
+    # Chercher le screenshot le plus récent dans TOUS les dossiers
+    all_shots = []
+    for pattern in ["bg_*/shots/heartbeat_*.png", "sess_*/shots/heartbeat_*.png",
+                     "*/bg_*/shots/heartbeat_*.png", "bg_*/shots/shot_*_full.png",
+                     "sess_*/shots/shot_*_full.png"]:
+        all_shots.extend(live_dir.glob(pattern))
+
+    if not all_shots:
+        return jsonify({'error': 'Aucun screenshot Windows. Lancez l\'agent V1 sur le PC cible.'}), 404
+
+    # Trier par date de modification (le plus récent en premier)
+    all_shots.sort(key=lambda p: p.stat().st_mtime, reverse=True)
+    latest_shot = all_shots[0]
+    age_seconds = _time.time() - latest_shot.stat().st_mtime
 
     if not latest_shot:
         return jsonify({'error': 'Aucun screenshot Windows disponible'}), 404
@@ -169,6 +172,8 @@ def capture_windows():
             'source': 'windows',
             'file': str(latest_shot.name),
             'session': latest_shot.parent.parent.name,
+            'age_seconds': round(age_seconds, 1),
+            'fresh': age_seconds < 30,
         })
     except Exception as e:
         return jsonify({'error': str(e)}), 500
diff --git a/visual_workflow_builder/backend/api_v3/dag_execute.py b/visual_workflow_builder/backend/api_v3/dag_execute.py
index b141d1429..464efa348 100644
--- a/visual_workflow_builder/backend/api_v3/dag_execute.py
+++ b/visual_workflow_builder/backend/api_v3/dag_execute.py
@@ -879,6 +879,16 @@ def execute_windows():
     if not data:
         return jsonify({'error': 'Aucune donnée'}), 400
 
+    # Injecter un délai de 5s avant la première action
+    # pour laisser le temps à l'utilisateur de réduire le navigateur
+    if 'actions' in data and data['actions']:
+        data['actions'].insert(0, {
+            'type': 'wait',
+            'action_id': 'wait_before_start',
+            'parameters': {'duration_ms': 5000},
+            'text': '',
+        })
+
     # Mapper les types VWB → types executor Windows
     TYPE_MAP = {
         'click_anchor': 'click',
diff --git a/visual_workflow_builder/frontend_v4/src/components/CapturePanel.tsx b/visual_workflow_builder/frontend_v4/src/components/CapturePanel.tsx
index b3f04f3ca..a5296a5ba 100644
--- a/visual_workflow_builder/frontend_v4/src/components/CapturePanel.tsx
+++ b/visual_workflow_builder/frontend_v4/src/components/CapturePanel.tsx
@@ -111,9 +111,30 @@ export default function CapturePanel({
     }
   };
 
+  // Capture intelligente — auto-détection OS
+  const doSmartCapture = async () => {
+    const isWindows = navigator.platform?.includes('Win') || navigator.userAgent?.includes('Windows');
+    if (isWindows) {
+      try {
+        const resp = await fetch('/api/screen-capture/capture-windows', { method: 'POST' });
+        const data = await resp.json();
+        if (data.image) {
+          setCurrentCapture({
+            screenshot_base64: data.image,
+            width: data.width,
+            height: data.height,
+            source: 'windows',
+          } as any);
+        }
+      } catch {}
+    } else {
+      onCapture();
+    }
+  };
+
   const handleTimerCapture = () => {
     if (timerSeconds === 0) {
-      onCapture();
+      doSmartCapture();
       return;
     }
 
@@ -127,7 +148,7 @@ export default function CapturePanel({
       } else {
         clearInterval(interval);
         setCountdown(null);
-        onCapture();
+        doSmartCapture();
       }
     }, 1000);
   };
@@ -145,33 +166,10 @@ export default function CapturePanel({
     <div className="capture-panel">
       <h3>Capture</h3>
 
-      {/* Contrôles de capture */}
+      {/* Capture — auto-détection OS navigateur */}
       <div className="capture-controls">
-        <button onClick={onCapture} disabled={countdown !== null}>
-          Capturer
-        </button>
-        <button
-          onClick={async () => {
-            try {
-              const resp = await fetch('/api/screen-capture/capture-windows', { method: 'POST' });
-              const data = await resp.json();
-              if (data.image) {
-                const fakeCapture = {
-                  screenshot_base64: data.image,
-                  width: data.width,
-                  height: data.height,
-                  source: 'windows',
-                };
-                setCurrentCapture(fakeCapture as any);
-              }
-            } catch (err) {
-              console.error('Capture Windows échouée:', err);
-            }
-          }}
-          title="Capture le dernier écran du PC Windows"
-          style={{ fontSize: '12px' }}
-        >
-          🖥️ Windows
+        <button disabled={countdown !== null} onClick={doSmartCapture}>
+          📸 Capturer
         </button>
         <select value={timerSeconds} onChange={(e) => setTimerSeconds(Number(e.target.value))}>
           <option value="0">Immédiat</option>
diff --git a/visual_workflow_builder/frontend_v4/src/components/ExecutionControls.tsx b/visual_workflow_builder/frontend_v4/src/components/ExecutionControls.tsx
index e6477c5d3..383dcee4a 100644
--- a/visual_workflow_builder/frontend_v4/src/components/ExecutionControls.tsx
+++ b/visual_workflow_builder/frontend_v4/src/components/ExecutionControls.tsx
@@ -1,4 +1,5 @@
 // @ts-nocheck
+import { useState } from 'react';
 import type { Execution } from '../types';
 
 interface Props {
@@ -9,20 +10,19 @@ interface Props {
 
 export default function ExecutionControls({ execution, onStart, onStop }: Props) {
   const isRunning = execution?.status === 'running' || execution?.status === 'paused';
+  const [windowsStatus, setWindowsStatus] = useState<'idle' | 'sending' | 'sent' | 'error'>('idle');
 
   const handleExecuteWindows = async () => {
+    setWindowsStatus('sending');
     try {
-      // Récupérer le workflow actif depuis l'état de la session
       const stateResp = await fetch('/api/v3/session/state');
       const state = await stateResp.json();
       let workflowId = state?.session?.active_workflow_id;
       let steps = state?.workflow?.steps || [];
 
-      // Si pas de workflow actif, essayer de charger le premier disponible
       if (!steps.length && state?.workflows_list?.length) {
         const firstWf = state.workflows_list[0];
         workflowId = firstWf.id;
-        // Charger les étapes du workflow
         const wfResp = await fetch(`/api/v3/workflow/${firstWf.id}`);
         const wfData = await wfResp.json();
         steps = wfData?.steps || wfData?.workflow?.steps || [];
@@ -30,10 +30,10 @@ export default function ExecutionControls({ execution, onStart, onStop }: Props)
 
       if (!steps.length) {
         alert('Aucune étape dans le workflow. Sélectionnez un workflow d\'abord.');
+        setWindowsStatus('idle');
         return;
       }
 
-      // Via le proxy Vite (/api → port 5002)
       const resp = await fetch('/api/v3/execute-windows', {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
@@ -52,36 +52,50 @@ export default function ExecutionControls({ execution, onStart, onStop }: Props)
 
       const result = await resp.json();
       if (result.replay_id) {
-        alert(`Replay lancé sur Windows ! ID: ${result.replay_id}`);
+        setWindowsStatus('sent');
+        alert('Replay lancé ! Réduisez cette fenêtre maintenant.\nLes actions commenceront dans 5 secondes.');
+        setTimeout(() => setWindowsStatus('idle'), 5000);
       } else {
         alert(`Erreur: ${result.error || JSON.stringify(result)}`);
+        setWindowsStatus('error');
+        setTimeout(() => setWindowsStatus('idle'), 3000);
       }
     } catch (err) {
-      alert(`Erreur connexion streaming server: ${err}`);
+      alert(`Erreur connexion: ${err}`);
+      setWindowsStatus('error');
+      setTimeout(() => setWindowsStatus('idle'), 3000);
     }
   };
 
   return (
     <div className="execution-controls">
       {!isRunning ? (
-        <div style={{ display: 'flex', gap: '4px' }}>
-          <button className="btn-start" onClick={onStart}>
-            ▶️ Exécuter
+        <div style={{ display: 'flex', gap: '4px', alignItems: 'center' }}>
+          <button className="btn-start" onClick={onStart} title="Exécuter sur cet écran (Linux)">
+            🐧 Linux
           </button>
           <button
             className="btn-start"
             onClick={handleExecuteWindows}
-            style={{ background: '#0078d4', fontSize: '12px' }}
-            title="Envoyer les actions au PC Windows via le streaming server"
+            disabled={windowsStatus === 'sending'}
+            style={{
+              background: windowsStatus === 'sent' ? '#22c55e' : windowsStatus === 'error' ? '#ef4444' : '#0078d4',
+              fontSize: '12px',
+              opacity: windowsStatus === 'sending' ? 0.6 : 1,
+            }}
+            title="Exécuter sur le PC Windows distant"
           >
-            🖥️ Windows
+            {windowsStatus === 'sending' ? '⏳ Envoi...' :
+             windowsStatus === 'sent' ? '✅ Lancé !' :
+             windowsStatus === 'error' ? '❌ Erreur' :
+             '🖥️ Windows'}
           </button>
         </div>
       ) : (
         <>
           <div className="exec-status">
             <span className={`status-badge ${execution?.status}`}>
-              {execution?.status === 'running' ? 'En cours' : 'En pause'}
+              {execution?.status === 'running' ? '⏳ En cours' : '⏸️ En pause'}
             </span>
             <span className="exec-progress">
               {execution?.completed_steps}/{execution?.total_steps}
@@ -93,10 +107,6 @@ export default function ExecutionControls({ execution, onStart, onStop }: Props)
         </>
       )}
 
-      {execution?.status === 'completed' && (
-        <span className="status-badge completed">Terminé</span>
-      )}
-
       {execution?.status === 'error' && (
         <span className="status-badge error" title={execution.error_message}>
           Erreur