diff --git a/web_server.py b/web_server.py
index 7414f177..f0e47edb 100644
--- a/web_server.py
+++ b/web_server.py
@@ -4079,6 +4079,44 @@ def cancel_batch(batch_id):
         print(f"❌ Error cancelling batch {batch_id}: {e}")
         return jsonify({"success": False, "error": str(e)}), 500
 
+# NEW ENDPOINT: Add this function to web_server.py
+@app.route('/api/playlists/cleanup_batch', methods=['POST'])
+def cleanup_batch():
+    """
+    Cleans up a completed or cancelled batch from the server's in-memory state.
+    This is called by the client after the user closes a finished modal.
+    """
+    data = request.get_json()
+    batch_id = data.get('batch_id')
+    if not batch_id:
+        return jsonify({"success": False, "error": "Missing batch_id"}), 400
+
+    try:
+        with tasks_lock:
+            # Check if the batch exists before trying to delete
+            if batch_id in download_batches:
+                # Get the list of task IDs before deleting the batch
+                task_ids_to_remove = download_batches[batch_id].get('queue', [])
+                
+                # Delete the batch record
+                del download_batches[batch_id]
+                
+                # Clean up the associated tasks from the tasks dictionary
+                for task_id in task_ids_to_remove:
+                    if task_id in download_tasks:
+                        del download_tasks[task_id]
+                
+                print(f"✅ Cleaned up batch '{batch_id}' and its associated tasks from server state.")
+                return jsonify({"success": True, "message": f"Batch {batch_id} cleaned up."})
+            else:
+                # It's not an error if the batch is already gone
+                print(f"⚠️ Cleanup requested for non-existent batch '{batch_id}'. Already cleaned up?")
+                return jsonify({"success": True, "message": "Batch already cleaned up."})
+
+    except Exception as e:
+        print(f"❌ Error during batch cleanup for '{batch_id}': {e}")
+        return jsonify({"success": False, "error": str(e)}), 500
+
 # ===============================
 # == UNIFIED MISSING TRACKS API ==
 # ===============================
diff --git a/webui/static/script.js b/webui/static/script.js
index 37726bd2..0284e59a 100644
--- a/webui/static/script.js
+++ b/webui/static/script.js
@@ -1536,13 +1536,29 @@ function updatePlaylistCardUI(playlistId) {
     }
 }
 
-function cleanupDownloadProcess(playlistId) {
-    if (!activeDownloadProcesses[playlistId]) return;
+async function cleanupDownloadProcess(playlistId) {
+    const process = activeDownloadProcesses[playlistId];
+    if (!process) return;
 
     console.log(`Cleaning up download process for playlist ${playlistId}`);
-    const process = activeDownloadProcesses[playlistId];
 
-    // Stop polling
+    // --- THIS IS THE FIX ---
+    // If the process has a batchId, tell the server to clean it up.
+    if (process.batchId) {
+        try {
+            console.log(`🚀 Sending cleanup request to server for batch: ${process.batchId}`);
+            await fetch('/api/playlists/cleanup_batch', {
+                method: 'POST',
+                headers: { 'Content-Type': 'application/json' },
+                body: JSON.stringify({ batch_id: process.batchId })
+            });
+        } catch (error) {
+            console.error('Failed to send cleanup request to server:', error);
+        }
+    }
+    // --- END OF FIX ---
+
+    // Stop client-side polling
     if (process.poller) {
         clearInterval(process.poller);
     }
@@ -1552,7 +1568,7 @@ function cleanupDownloadProcess(playlistId) {
         process.modalElement.parentElement.removeChild(process.modalElement);
     }
 
-    // Remove from global state
+    // Remove from client-side global state
     delete activeDownloadProcesses[playlistId];
 
     // Restore card UI