diff --git a/frontend/src/pages/Watch.jsx b/frontend/src/pages/Watch.jsx
index 057b7de..e8dc555 100644
--- a/frontend/src/pages/Watch.jsx
+++ b/frontend/src/pages/Watch.jsx
@@ -697,24 +697,22 @@ export default function Watch() {
       .catch(() => { pollTimerRef.current = setTimeout(() => pollForFile(url), 1500); });
   }, [fileReady]);
 
+  // Only poll once the backend confirms the download is fully written.
+  // Polling before status==="complete" risks playing a partial file.
   useEffect(() => {
-    if (!dlStatus?.file_url || fileReady || !playRequested) return;
-    pollForFile(dlStatus.file_url);
+    if (fileReady || !playRequested) return;
+    const backendDone = dlStatus?.status === "complete" || !!video?.is_downloaded;
+    const fileUrl = dlStatus?.file_url ?? (video?.is_downloaded ? `/files/${youtubeVideoId}.mp4` : null);
+    if (!backendDone || !fileUrl) return;
+    pollForFile(fileUrl);
     return () => clearTimeout(pollTimerRef.current);
-  }, [dlStatus?.file_url, fileReady, pollForFile, playRequested]);
-
-  useEffect(() => {
-    if (!video?.is_downloaded || fileReady || !playRequested) return;
-    pollForFile(`/files/${youtubeVideoId}.mp4`);
-  }, [video?.is_downloaded, playRequested]); // eslint-disable-line react-hooks/exhaustive-deps
+  }, [playRequested, fileReady, dlStatus?.status, dlStatus?.file_url, video?.is_downloaded, youtubeVideoId, pollForFile]); // eslint-disable-line react-hooks/exhaustive-deps
 
   const downloadMut = useMutation({
     mutationFn: () => createDownload(youtubeVideoId, selectedQuality),
     onSuccess: (res) => {
-      const dl = res.data;
-      setDownloadId(dl.id);
+      setDownloadId(res.data.id);
       refetchVideo();
-      if (dl.status === "complete" && dl.file_url) pollForFile(dl.file_url);
     },
   });