diff --git a/movie_editor/frontend/api.js b/movie_editor/frontend/api.js
index 06f687c4..5e9bc797 100644
--- a/movie_editor/frontend/api.js
+++ b/movie_editor/frontend/api.js
@@ -130,13 +130,8 @@
     gitCheckout: (branch) => j("POST", API("/git/checkout"), { branch }),
 
     // generate (a single scene, or an explicit run of scene ids = one chain request)
-    generate: (id, onlyScene, sceneIds, resetSession, timelineSnapshot) =>
-      j("POST", API(`/projects/${id}/generate`), {
-        only_scene: onlyScene || null,
-        scene_ids: sceneIds || null,
-        reset_session: !!resetSession,
-        timeline_snapshot: timelineSnapshot || null,
-      }),
+    generate: (id, onlyScene, sceneIds, resetSession) =>
+      j("POST", API(`/projects/${id}/generate`), { only_scene: onlyScene || null, scene_ids: sceneIds || null, reset_session: !!resetSession }),
     status: (id, promptId) => j("GET", API(`/projects/${id}/status/${promptId}`)),
     progress: () => j("GET", API("/progress")),
     livePreview: () => j("GET", API("/live-preview")),
@@ -161,7 +156,6 @@
           type: m.type || "output",
           render_in: String(spec.renderIn != null ? spec.renderIn : 0),
         });
-        if (spec.cacheBust != null) q.set("v", String(spec.cacheBust));
         u += "?" + q.toString();
       }
       return u;
diff --git a/movie_editor/frontend/player.js b/movie_editor/frontend/player.js
index d89eb72e..80e4fdcd 100644
--- a/movie_editor/frontend/player.js
+++ b/movie_editor/frontend/player.js
@@ -158,8 +158,7 @@
         const sc = S.scene(c.sceneId);
         const sourceIn = sc?.source_in || 0;
         const renderIn = Math.max(0, (c.inSec || 0) - sourceIn);
-        const cacheBust = (st && st._previewGenToken) || Date.now();
-        c.streamUrl = API.previewSegmentUrl(pid, c.sceneId, { media: c.media, renderIn, cacheBust });
+        c.streamUrl = API.previewSegmentUrl(pid, c.sceneId, { media: c.media, renderIn });
       }
     }
   }
@@ -922,8 +921,6 @@
     }
     if (g.livePreviewUrl) {
       _ensureLivePreviewDom();
-      const canvas = document.querySelector(".pm-canvas");
-      if (canvas && !canvas.classList.contains("gen-live-preview")) canvas.classList.add("gen-live-preview");
       if (_livePreviewLayerEl) _livePreviewLayerEl.style.display = "";
       if (_livePreviewEl && _livePreviewEl.src !== g.livePreviewUrl) _livePreviewEl.src = g.livePreviewUrl;
       if (_livePreviewEl) _livePreviewEl.style.display = "";
@@ -1098,9 +1095,6 @@
 
     // Rebuilding the monitor DOM during playback detaches <video> nodes and kills multi-scene
     // chain preview mid-stream (often visible from scene 3 onward once store ticks catch up).
-    // Still mount live preview during generation so sampling frames stay visible while playing.
-    const genActive = ["queuing", "running", "pending"].includes(st.gen?.state);
-    if (genActive && _livePreviewConfigured(st)) _ensureLivePreviewDom();
     if (_scrubDepth > 0 || _playing) {
       _ensureStageMounted();
       return;
@@ -1114,8 +1108,7 @@
     const previewOverlay = previewAsset && (previewAsset.kind === "image" || previewAsset.kind === "audio" || previewAsset.kind === "video");
 
     // ── canvas (video + placeholder) ────────────────────────────────────────
-    const genLive = ["queuing", "running", "pending"].includes(gen.state) && _livePreviewConfigured(st);
-    const canvas = el("div", "pm-canvas" + (previewOverlay ? " media-previewing" : "") + (genLive ? " gen-live-preview" : ""));
+    const canvas = el("div", "pm-canvas" + (previewOverlay ? " media-previewing" : ""));
     _slateEl = el("div", "pm-slate");
     _slateEl.style.display = "none";
     _slateEl.append(el("div", "pm-slate-title"));
diff --git a/movie_editor/frontend/store.js b/movie_editor/frontend/store.js
index a2ff79ea..97123fb5 100644
--- a/movie_editor/frontend/store.js
+++ b/movie_editor/frontend/store.js
@@ -828,7 +828,6 @@
       _syncEditorStateToProject();
       snapshot.scene_renders = state.project.scene_renders;
       snapshot.scene_ghosts = state.project.scene_ghosts;
-      snapshot.models = state.project.models;
       const previewKeyBefore = _promptPreviewKey(snapshot);
       const selBefore = JSON.stringify(state.selectedSceneIds || []);
       const metaBefore = { name: snapshot.name, scene_count: (snapshot.scenes || []).length };
@@ -840,12 +839,7 @@
         // If the user edited again while this save was in flight (e.g. dropped a new
         // anchor), do NOT replace local state with the older snapshot we just wrote.
         if (_localDirty) scheduleSave();
-        else {
-          state.project = saved;
-          // Keep in-memory renders if a run finished while this save was in flight.
-          state.project.scene_renders = JSON.parse(JSON.stringify(state.sceneRenders || {}));
-          state.project.scene_ghosts = JSON.parse(JSON.stringify(state.sceneGhosts || []));
-        }
+        else state.project = saved;
         state.saving = false;
         _pruneSelection();
         const selChanged = JSON.stringify(state.selectedSceneIds || []) !== selBefore;
@@ -2412,8 +2406,6 @@
     [/Node registry unavailable/i, "ComfyUI is offline or still starting up — wait a moment and try again."],
     [/HTTP 53[0-9]|HTTP 52[24]|HTTP 502|Failed to fetch|NetworkError|Load failed/i,
       "Cloudflare tunnel lost contact with the vast.ai instance. GPU work may still be running — wait, refresh, and check ComfyUI output. If it keeps failing, use vast.ai direct port access or restart the tunnel."],
-    [/Timeline on the server|Timeline did not save|does not match the editor/i,
-      "Timeline did not save before generate. Wait for the save indicator to clear, then try again."],
   ];
 
   function _isTransientTunnelError(err) {
@@ -2441,24 +2433,7 @@
     return flushSave();
   }
 
-  function _generationTimelineSnap(project, sceneIds) {
-    if (!project) return { anchor: "", scenes: [] };
-    const ids = sceneIds && sceneIds.length ? new Set(sceneIds) : null;
-    const scenes = (project.scenes || [])
-      .filter((s) => !s.excluded && isGenerativeScene(s))
-      .filter((s) => !ids || ids.has(s.id))
-      .map((s) => ({
-        id: s.id,
-        text: s.text || "",
-        source: {
-          type: (s.source && s.source.type) || "carry",
-          media_ref: (s.source && s.source.media_ref) || null,
-        },
-      }));
-    return { anchor: (project.anchor || "").trim(), scenes };
-  }
-
-  async function _flushSaveForGenerate(sceneIds) {
+  async function _flushSaveForGenerate() {
     await flushPendingEdits();
     if (_localDirty) {
       throw new Error(
@@ -2466,16 +2441,6 @@
         + "Wait for the save indicator to clear, then try again."
       );
     }
-    const localSnap = _generationTimelineSnap(state.project, sceneIds);
-    const saved = await _retryOnTunnel(() => API.getProject(state.project.id));
-    const serverSnap = _generationTimelineSnap(saved, sceneIds);
-    if (JSON.stringify(localSnap) !== JSON.stringify(serverSnap)) {
-      throw new Error(
-        "Timeline did not save before generate. Wait for the save indicator to clear, then try again."
-      );
-    }
-    state._previewGenToken = Date.now();
-    return localSnap;
   }
 
   function _sleep(ms) {
@@ -2786,10 +2751,8 @@
     if (recordedSceneIds.length) {
       _validateRendersToken++;
       state.notice = "";
-      state._previewGenToken = Date.now();
       _syncEditorStateToProject();
       scheduleSaveSilent();
-      notify();
     }
   }
 
@@ -2937,15 +2900,8 @@
     _markGenInFlight(sceneIds);
     set({ gen: { state: "queuing", promptId: null, media: [], msg: `${prefix}: queuing…`, step: 0, maxStep: 0, livePreviewUrl: null, liveScene: -1, liveSceneCount: 0 } });
     try {
-      const timelineSnapshot = _generationTimelineSnap(state.project, sceneIds);
       const r = await _retryOnTunnel(
-        () => API.generate(
-          state.project.id,
-          onlyScene || null,
-          onlyScene ? null : sceneIds,
-          !!resetSession,
-          timelineSnapshot,
-        ),
+        () => API.generate(state.project.id, onlyScene || null, onlyScene ? null : sceneIds, !!resetSession),
         10,
       );
       if (!r.prompt_id) { set({ gen: { ...state.gen, state: "error", msg: "No prompt id returned." } }); return false; }
@@ -2979,17 +2935,17 @@
 
   async function generate(onlyScene) {
     if (!state.project) return;
-    if (!onlyScene) return generateMontage();
-    const sc = scene(onlyScene);
-    const ids = sc ? genUnitSceneIds(genUnitId(sc)) : [onlyScene];
     try {
-      await _flushSaveForGenerate(ids);
+      await _flushSaveForGenerate();
     } catch (e) {
       set({ gen: { state: "error", promptId: null, media: [], msg: _friendlyGenError(e.message) } });
       return;
     }
+    if (!onlyScene) return generateMontage();
     const reset = _resetSessionPending; _resetSessionPending = false;
     if (reset) state.resetSessionArmed = false;
+    const sc = scene(onlyScene);
+    const ids = sc ? genUnitSceneIds(genUnitId(sc)) : [onlyScene];
     await _generateRun(ids, onlyScene, "Generating scene", reset);
   }
 
@@ -2998,13 +2954,13 @@
   // session reset applies to the FIRST run only.
   async function generateMontage() {
     if (!state.project) return;
-    const runs = _runs();
     try {
-      await _flushSaveForGenerate(runs.flat());
+      await _flushSaveForGenerate();
     } catch (e) {
       set({ gen: { state: "error", promptId: null, media: [], msg: _friendlyGenError(e.message) } });
       return;
     }
+    const runs = _runs();
     if (!runs.length) { set({ gen: { state: "error", promptId: null, media: [], msg: "No active scenes to generate." } }); return; }
     const reset = _resetSessionPending; _resetSessionPending = false;
     if (reset) state.resetSessionArmed = false;
@@ -3025,13 +2981,13 @@
       set({ gen: { state: "error", promptId: null, media: [], msg: "No scenes selected." } });
       return;
     }
-    const runs = _runsForSceneIds(ids);
     try {
-      await _flushSaveForGenerate(runs.flat());
+      await _flushSaveForGenerate();
     } catch (e) {
       set({ gen: { state: "error", promptId: null, media: [], msg: _friendlyGenError(e.message) } });
       return;
     }
+    const runs = _runsForSceneIds(ids);
     if (!runs.length) {
       set({ gen: { state: "error", promptId: null, media: [], msg: "No generatable runs in the selection." } });
       return;
diff --git a/movie_editor/frontend/styles.css b/movie_editor/frontend/styles.css
index 7ae8eb85..11fb8a18 100644
--- a/movie_editor/frontend/styles.css
+++ b/movie_editor/frontend/styles.css
@@ -448,8 +448,6 @@ input[type=number] { font-family: var(--font-mono); }
 .gen-readout .pulse { width: 8px; height: 8px; border-radius: 50%; background: var(--amber); animation: pulse 1s infinite; flex: 0 0 auto; }
 .gen-readout.error { color: var(--danger); }
 .gen-readout.error .pulse { background: var(--danger); animation: none; }
-.pm-canvas.gen-live-preview .pm-stage { opacity: 0.12; }
-.pm-canvas.gen-live-preview .pm-live-preview { z-index: 4; }
 .pm-live-preview { position: absolute; inset: 12px 12px 52px 12px; display: flex; align-items: center; justify-content: center; pointer-events: none; z-index: 3; }
 .pm-live-preview-img { max-width: 100%; max-height: 100%; object-fit: contain; border-radius: 6px; border: 1px solid var(--line); box-shadow: 0 8px 32px #000a; background: #0006; }
 .pm-live-preview-badge { position: absolute; top: 8px; left: 8px; font-family: var(--font-mono); font-size: 11px; color: var(--amber-2); background: #000b; border: 1px solid var(--line); padding: 3px 8px; border-radius: 12px; }
diff --git a/movie_editor/server.py b/movie_editor/server.py
index 44d8710e..17716f48 100644
--- a/movie_editor/server.py
+++ b/movie_editor/server.py
@@ -200,33 +200,10 @@ def _scene_playback_clip_spec(
 _preview_segment_cache: dict[str, str] = {}
 
 
-def _invalidate_preview_segment_cache(pid: str) -> None:
-    """Drop cached ffmpeg trims when a project re-generates or source files change."""
-    import os
-    prefix = f"{pid}:"
-    for key in list(_preview_segment_cache.keys()):
-        if not key.startswith(prefix):
-            continue
-        cached = _preview_segment_cache.pop(key, None)
-        if cached:
-            try:
-                os.unlink(cached)
-            except OSError:
-                pass
-
-
-def _source_mtime(path: str) -> int:
-    import os
-    try:
-        return int(os.path.getmtime(path))
-    except OSError:
-        return 0
-
-
-def _preview_segment_cache_key(pid: str, scene_id: str, clip: dict, *, src_mtime: int = 0) -> str:
+def _preview_segment_cache_key(pid: str, scene_id: str, clip: dict) -> str:
     return (
         f"{pid}:{scene_id}:{clip.get('filename')}:{clip.get('subfolder') or ''}:"
-        f"{clip.get('type') or 'output'}:{clip.get('in')}:{clip.get('dur')}:mt{int(src_mtime or 0)}"
+        f"{clip.get('type') or 'output'}:{clip.get('in')}:{clip.get('dur')}"
     )
 
 
@@ -359,40 +336,6 @@ def _parse_prompt_variants(prompt: str, seed: int) -> tuple[dict, dict]:
     )
 
 
-def _timeline_snapshot_mismatch(snapshot: Optional[dict], target: Project) -> Optional[str]:
-    """Return a short label when the saved project does not match the editor snapshot."""
-    from .backend.timeline import is_generative_scene, source_type
-
-    if not isinstance(snapshot, dict):
-        return None
-    exp_by_id: dict[str, dict] = {}
-    for raw in snapshot.get("scenes") or []:
-        if isinstance(raw, dict) and raw.get("id"):
-            exp_by_id[str(raw["id"])] = raw
-    if not exp_by_id:
-        return None
-    exp_anchor = str(snapshot.get("anchor") or "").strip()
-    if exp_anchor != str(getattr(target, "anchor", None) or "").strip():
-        return "project anchor"
-    for sc in target.scenes:
-        if sc.excluded or not is_generative_scene(sc):
-            continue
-        sid = str(sc.id)
-        if sid not in exp_by_id:
-            continue
-        exp = exp_by_id[sid]
-        if str(exp.get("text") or "") != str(sc.text or ""):
-            return f"scene {sid} prompt"
-        exp_src = exp.get("source") if isinstance(exp.get("source"), dict) else {}
-        st = source_type(sc)
-        if str(exp_src.get("type") or "carry") != st:
-            return f"scene {sid} source mode"
-        ref = getattr(sc.source, "media_ref", None) if sc.source else None
-        if (exp_src.get("media_ref") or None) != ref:
-            return f"scene {sid} anchor image"
-    return None
-
-
 def _project_models(p: Optional[Project]) -> dict:
     """The project's own pipeline config, or the global default when it has none yet."""
     m = getattr(p, "models", None)
@@ -1421,23 +1364,13 @@ if web is not None and PromptServer is not None:
     # --- API: generate / status / result ---
     @routes.post(UI_PREFIX + "/api/projects/{pid}/generate")
     async def _generate(req):
-        pid = req.match_info["pid"]
-        _invalidate_preview_segment_cache(pid)
-        p = _project_or_404(pid)
+        p = _project_or_404(req.match_info["pid"])
         body = await req.json() if req.can_read_body else {}
         scene_ids = body.get("scene_ids")
         if scene_ids:
             target = _segment(p, scene_ids)
         else:
             target = _solo(p, body.get("only_scene"))
-        mismatch = _timeline_snapshot_mismatch(body.get("timeline_snapshot"), target)
-        if mismatch:
-            return web.json_response({
-                "detail": (
-                    f"Timeline on the server does not match the editor ({mismatch}). "
-                    "Wait for save to finish, reload the project, then generate again."
-                ),
-            }, status=409)
         try:
             validation = bridge.validate_generation_prompt(p, target)
         except Exception as e:  # noqa: BLE001
@@ -1714,15 +1647,10 @@ if web is not None and PromptServer is not None:
             clip = _scene_playback_clip_spec(proj, scene_id, render_override=render_override)
         except KeyError as e:
             return web.json_response({"detail": str(e)}, status=404)
-        try:
-            src_path = _resolve_clip_src_path(clip)
-        except FileNotFoundError as e:
-            return web.json_response({"detail": str(e)}, status=400)
-        src_mtime = _source_mtime(src_path)
-        key = _preview_segment_cache_key(pid, scene_id, clip, src_mtime=src_mtime)
+        key = _preview_segment_cache_key(pid, scene_id, clip)
         cached = _preview_segment_cache.get(key)
         if cached and os.path.isfile(cached):
-            return web.FileResponse(cached, headers={"Cache-Control": "private, max-age=60"})
+            return web.FileResponse(cached, headers={"Cache-Control": "private, max-age=3600"})
         try:
             import folder_paths
             tempdir = folder_paths.get_temp_directory()
@@ -1734,13 +1662,14 @@ if web is not None and PromptServer is not None:
             f"funpack_preview_{pid[:8]}_{scene_id}_{int(_time.time() * 1000)}.mp4",
         )
         try:
+            src_path = _resolve_clip_src_path(clip)
             _ffmpeg_trim_clip(src_path, out_path, clip.get("in"), clip.get("dur"))
         except FileNotFoundError as e:
             return web.json_response({"detail": str(e)}, status=400)
         except RuntimeError as e:
             return web.json_response({"detail": str(e)}, status=503)
         _preview_segment_cache[key] = out_path
-        return web.FileResponse(out_path, headers={"Cache-Control": "private, max-age=60"})
+        return web.FileResponse(out_path, headers={"Cache-Control": "private, max-age=3600"})
 
     # --- API: export one clip (ffmpeg trim from a chain output using in/dur) ---
     @routes.post(UI_PREFIX + "/api/projects/{pid}/export-clip")
diff --git a/movie_editor/tests/test_server.py b/movie_editor/tests/test_server.py
index 1df5dd4a..fde7b429 100644
--- a/movie_editor/tests/test_server.py
+++ b/movie_editor/tests/test_server.py
@@ -356,71 +356,4 @@ def test_build_render_filter_blank_canvas():
     )
     assert "[0:v]format=yuv420p,setsar=1[vbase]" in filt
     assert "[aout]" in filt
-    assert has_audio is True
-
-
-def test_timeline_snapshot_mismatch_detects_stale_anchor():
-    from movie_editor.backend.timeline import Scene, SceneSource
-    from movie_editor.server import _timeline_snapshot_mismatch
-
-    p = Project(
-        name="t",
-        anchor="new anchor",
-        scenes=[
-            Scene(id="s1", text="scene one", source=SceneSource(type="image", media_ref="img_b")),
-            Scene(id="s2", text="scene two", source=SceneSource(type="carry")),
-        ],
-    )
-    snap = {
-        "anchor": "new anchor",
-        "scenes": [
-            {"id": "s1", "text": "scene one", "source": {"type": "image", "media_ref": "img_a"}},
-            {"id": "s2", "text": "scene two", "source": {"type": "carry", "media_ref": None}},
-        ],
-    }
-    assert _timeline_snapshot_mismatch(snap, p) == "scene s1 anchor image"
-
-
-def test_timeline_snapshot_mismatch_none_when_aligned():
-    from movie_editor.backend.timeline import Scene, SceneSource
-    from movie_editor.server import _timeline_snapshot_mismatch
-
-    p = Project(
-        name="t",
-        anchor="anchor",
-        scenes=[
-            Scene(id="s1", text="one", source=SceneSource(type="image", media_ref="img_a")),
-            Scene(id="s2", text="two", source=SceneSource(type="carry")),
-        ],
-    )
-    snap = {
-        "anchor": "anchor",
-        "scenes": [
-            {"id": "s1", "text": "one", "source": {"type": "image", "media_ref": "img_a"}},
-            {"id": "s2", "text": "two", "source": {"type": "carry", "media_ref": None}},
-        ],
-    }
-    assert _timeline_snapshot_mismatch(snap, p) is None
-
-
-def test_preview_segment_cache_key_includes_source_mtime():
-    from movie_editor.server import _preview_segment_cache_key
-
-    clip = {"filename": "chain.mp4", "subfolder": "", "type": "temp", "in": 0.0, "dur": 2.6}
-    k1 = _preview_segment_cache_key("p1", "s1", clip, src_mtime=100)
-    k2 = _preview_segment_cache_key("p1", "s1", clip, src_mtime=200)
-    assert k1 != k2
-
-
-def test_invalidate_preview_segment_cache_drops_project_entries(tmp_path, monkeypatch):
-    from movie_editor import server
-
-    stale = tmp_path / "stale.mp4"
-    stale.write_bytes(b"x")
-    server._preview_segment_cache.clear()
-    server._preview_segment_cache["p1:s1:chain.mp4:::temp:0:2.6:mt1"] = str(stale)
-    server._preview_segment_cache["p2:s1:other.mp4:::temp:0:1:mt1"] = str(tmp_path / "keep.mp4")
-    server._invalidate_preview_segment_cache("p1")
-    assert not any(k.startswith("p1:") for k in server._preview_segment_cache)
-    assert any(k.startswith("p2:") for k in server._preview_segment_cache)
-    assert not stale.exists()
\ No newline at end of file
+    assert has_audio is True
\ No newline at end of file