diff --git a/packages/core/src/generated/position-edits-render-inline.ts b/packages/core/src/generated/position-edits-render-inline.ts
index f1660ea00d..030b1e1556 100644
--- a/packages/core/src/generated/position-edits-render-inline.ts
+++ b/packages/core/src/generated/position-edits-render-inline.ts
@@ -1,6 +1,6 @@
 // Generated by scripts/build-position-edits-render.ts; do not edit.
 const POSITION_EDITS_RENDER_IIFE: string =
-  '"use strict";(()=>{function x(){return globalThis}function P(e,t){if(typeof window>"u")return;let o=x(),r=o.__hf?.onSwallowed;if(r)try{r({label:e,error:t})}catch(s){}(o.__hfDebug||o.__HYPERFRAMES_DEBUG)&&console.debug(`[hyperframes] ${e} swallowed:`,t)}var T=null;function R(e,t){if(T)try{T({source:"hf-preview",type:"analytics",event:e,properties:t??{}})}catch(o){P("runtime.analytics.site1",o)}}var M="http://www.w3.org/1999/xhtml";function N(e){return e!=null&&e.nodeType===1}function _(e){return N(e)&&(e.namespaceURI===M||e.namespaceURI==="http://www.w3.org/2000/svg")}var y="data-hf-edit-base-x",w="data-hf-edit-base-y",m="data-hf-edit-original-translate",k=e=>{let t=parseFloat(e??"");return Number.isFinite(t)?t:0},C=e=>{let t=[],o=0,r="";for(let s of e.trim())s==="("&&(o+=1),s===")"&&(o=Math.max(0,o-1)),/\\s/.test(s)&&o===0?(r&&t.push(r),r=""):r+=s;return r&&t.push(r),t},$=/^-?(?:\\d+(?:\\.\\d+)?|\\.\\d+)px$/,E=(e,t)=>$.test(e)&&$.test(t)?`${parseFloat(e)+parseFloat(t)}px`:`calc(${e} + ${t})`,O=(e,t,o)=>{if(!e||e==="none")return`${t} ${o}`;let[r,s,a]=C(e);if(r===void 0)return`${t} ${o}`;if(s===void 0)return`${E(r,t)} ${o}`;let i=a===void 0?"":` ${a}`;return`${E(r,t)} ${E(s,o)}${i}`},j=e=>{try{e.ownerDocument.defaultView?.gsap?.getProperty?.(e,"x")}catch{}},V=e=>{let t=e.style.getPropertyValue("translate").trim();if(t)return t==="none"?"":t;try{let o=e.ownerDocument.defaultView,r=o?o.getComputedStyle(e).getPropertyValue("translate").trim():"";return r==="none"?"":r}catch{return""}},b=new WeakMap;function B(e,t){let o=b.get(e);if(!t?.force&&o!==void 0&&e.style.getPropertyValue("translate")!==o){R("position_edit_fold_skipped",{hfId:e.getAttribute("data-hf-id")});return}let r=k(e.getAttribute("data-x"))-k(e.getAttribute(y)),s=k(e.getAttribute("data-y"))-k(e.getAttribute(w));e.hasAttribute(m)||e.setAttribute(m,V(e)),o===void 0&&j(e);let a=e.getAttribute(m)??"",i=O(a,`${r}px`,`${s}px`);e.style.setProperty("translate",i),b.set(e,e.style.getPropertyValue("translate"))}function h(e,t){let o=e.querySelectorAll(`[${m}]:not([${y}]):not([${w}])`);for(let a=0;a<o.length;a++){let i=o[a];if(i===void 0||!_(i))continue;let g=i.getAttribute(m)??"";g===""?i.style.removeProperty("translate"):i.style.setProperty("translate",g),i.removeAttribute(m),b.delete(i)}let r=e.querySelectorAll(`[${y}], [${w}]`),s=0;for(let a=0;a<r.length;a++){let i=r[a];i===void 0||!_(i)||(B(i,t),s+=1)}return s}var L="__hfPositionEditsSeekReapplyWrapped",D=new WeakSet,F=new WeakMap,H=new WeakMap;function W(e){let t=e,o=()=>{try{h(t.document)}catch{}},r=n=>typeof n=="function"&&(D.has(n)||!!n[L]),s=n=>{D.add(n);try{Object.defineProperty(n,L,{value:!0})}catch{}},a=n=>{if(typeof n!="function"||r(n))return n;let l=function(...u){let d=n.apply(this,u);return o(),d};return s(l),l},i=(n,l)=>{let u=F.get(n);if(u?.has(l))return!0;let d=Object.getOwnPropertyDescriptor(n,l);if(d?.configurable===!1){let c=n[l];return typeof c=="function"&&(n[l]=a(c),o()),!1}let p=n[l],f=d?.set;return Object.defineProperty(n,l,{configurable:!0,enumerable:d?.enumerable??!0,get:()=>p,set:c=>{p=a(c),f?.call(n,c)}}),p=a(p),u??(u=new Set),u.add(l),F.set(n,u),o(),!0},g=(n,l)=>{let u=H.get(t),d=Object.getOwnPropertyDescriptor(t,n);if(!u?.has(n)){if(d?.configurable===!1){let c=t[n];return c?i(c,l):!1}let f=t[n];Object.defineProperty(t,n,{configurable:!0,enumerable:d?.enumerable??!0,get:()=>f,set:c=>{f=c,f&&i(f,l)}}),u??(u=new Set),u.add(n),H.set(t,u)}let p=t[n];return p?i(p,l):!1},S=()=>{let n=g("__hf","seek"),l=g("__player","renderSeek");return n&&l};if(S())return;let v=120,A=t.setInterval(()=>{if(S()){t.clearInterval(A);return}v-=1,v<=0&&t.clearInterval(A)},50)}function I(){document.querySelector(`[${y}], [${w}]`)&&(h(document),W(window))}document.readyState==="loading"?document.addEventListener("DOMContentLoaded",I,{once:!0}):I();})();\n';
+  '"use strict";(()=>{function x(){return globalThis}function T(e,t){if(typeof window>"u")return;let o=x(),r=o.__hf?.onSwallowed;if(r)try{r({label:e,error:t})}catch(s){}(o.__hfDebug||o.__HYPERFRAMES_DEBUG)&&console.debug(`[hyperframes] ${e} swallowed:`,t)}var P=null;function R(e,t){if(P)try{P({source:"hf-preview",type:"analytics",event:e,properties:t??{}})}catch(o){T("runtime.analytics.site1",o)}}var I="http://www.w3.org/1999/xhtml";function N(e){return e!=null&&e.nodeType===1}function _(e){return N(e)&&(e.namespaceURI===I||e.namespaceURI==="http://www.w3.org/2000/svg")}var y="data-hf-edit-base-x",w="data-hf-edit-base-y",m="data-hf-edit-original-translate",k=e=>{let t=parseFloat(e??"");return Number.isFinite(t)?t:0},C=e=>{let t=[],o=0,r="";for(let s of e.trim())s==="("&&(o+=1),s===")"&&(o=Math.max(0,o-1)),/\\s/.test(s)&&o===0?(r&&t.push(r),r=""):r+=s;return r&&t.push(r),t},$=/^-?(?:\\d+(?:\\.\\d+)?|\\.\\d+)px$/,E=(e,t)=>$.test(e)&&$.test(t)?`${parseFloat(e)+parseFloat(t)}px`:`calc(${e} + ${t})`,O=(e,t,o)=>{if(!e||e==="none")return`${t} ${o}`;let[r,s,a]=C(e);if(r===void 0)return`${t} ${o}`;if(s===void 0)return`${E(r,t)} ${o}`;let i=a===void 0?"":` ${a}`;return`${E(r,t)} ${E(s,o)}${i}`},j=e=>{try{e.ownerDocument.defaultView?.gsap?.getProperty?.(e,"x")}catch{}},V=e=>{let t=e.style.getPropertyValue("translate").trim();if(t)return t==="none"?"":t;try{let o=e.ownerDocument.defaultView,r=o?o.getComputedStyle(e).getPropertyValue("translate").trim():"";return r==="none"?"":r}catch{return""}},b=new WeakMap;function B(e,t){let o=b.get(e);if(!t?.force&&o!==void 0&&e.style.getPropertyValue("translate")!==o){R("position_edit_fold_skipped",{hfId:e.getAttribute("data-hf-id")});return}let r=k(e.getAttribute("data-x"))-k(e.getAttribute(y)),s=k(e.getAttribute("data-y"))-k(e.getAttribute(w));e.hasAttribute(m)||e.setAttribute(m,V(e)),o===void 0&&j(e);let a=e.getAttribute(m)??"",i=O(a,`${r}px`,`${s}px`);e.style.setProperty("translate",i),b.set(e,e.style.getPropertyValue("translate"))}function S(e,t){let o=e.querySelectorAll(`[${m}]:not([${y}]):not([${w}])`);for(let a=0;a<o.length;a++){let i=o[a];if(i===void 0||!_(i))continue;let g=i.getAttribute(m)??"";g===""?i.style.removeProperty("translate"):i.style.setProperty("translate",g),i.removeAttribute(m),b.delete(i)}let r=e.querySelectorAll(`[${y}], [${w}]`),s=0;for(let a=0;a<r.length;a++){let i=r[a];i===void 0||!_(i)||(B(i,t),s+=1)}return s}var L="__hfPositionEditsSeekReapplyWrapped",D=new WeakSet,F=new WeakMap,H=new WeakMap;function M(e){let t=e,o=()=>{try{S(t.document)}catch{}},r=n=>typeof n=="function"&&(D.has(n)||!!n[L]),s=n=>{D.add(n);try{Object.defineProperty(n,L,{value:!0})}catch{}},a=n=>{if(typeof n!="function"||r(n))return n;let l=function(...u){let d=n.apply(this,u);return o(),d};return s(l),l},i=(n,l)=>{let u=F.get(n);if(u?.has(l))return!0;let d=Object.getOwnPropertyDescriptor(n,l);if(d?.configurable===!1){let c=n[l];return typeof c=="function"&&(n[l]=a(c),o()),!1}let p=n[l],f=d?.set;return Object.defineProperty(n,l,{configurable:!0,enumerable:d?.enumerable??!0,get:()=>p,set:c=>{p=a(c),f?.call(n,c)}}),p=a(p),u??(u=new Set),u.add(l),F.set(n,u),o(),!0},g=(n,l)=>{let u=H.get(t),d=Object.getOwnPropertyDescriptor(t,n);if(!u?.has(n)){if(d?.configurable===!1){let c=t[n];return c?i(c,l):!1}let f=t[n];Object.defineProperty(t,n,{configurable:!0,enumerable:d?.enumerable??!0,get:()=>f,set:c=>{f=c,f&&i(f,l)}}),u??(u=new Set),u.add(n),H.set(t,u)}let p=t[n];return p?i(p,l):!1},h=()=>{let n=g("__hf","seek"),l=g("__player","renderSeek");return n&&l};if(h())return;let v=120,A=t.setInterval(()=>{if(h()){t.clearInterval(A);return}v-=1,v<=0&&t.clearInterval(A)},50)}function W(){document.querySelector(`[${y}], [${w}]`)&&(S(document),M(window))}document.readyState==="loading"?document.addEventListener("DOMContentLoaded",W,{once:!0}):W();})();\n';
 
 /** Returns the pre-built position-edits render IIFE as a string constant. */
 export function getPositionEditsRenderScript(): string {
diff --git a/packages/core/src/runtime/domRealm.ts b/packages/core/src/runtime/domRealm.ts
index 2758e0581f..9b1c0d1a49 100644
--- a/packages/core/src/runtime/domRealm.ts
+++ b/packages/core/src/runtime/domRealm.ts
@@ -76,6 +76,11 @@ export function isAudioElement(value: unknown): value is HTMLAudioElement {
   return isHtmlTag(value, "audio");
 }
 
+/** `<source>`, from any realm. Mirrors `instanceof HTMLSourceElement`. */
+export function isSourceElement(value: unknown): value is HTMLSourceElement {
+  return isHtmlTag(value, "source");
+}
+
 /** `<video>` or `<audio>`, from any realm. Mirrors `instanceof HTMLMediaElement`. */
 export function isMediaElement(value: unknown): value is HTMLMediaElement {
   return isVideoElement(value) || isAudioElement(value);
diff --git a/packages/core/src/runtime/init.ts b/packages/core/src/runtime/init.ts
index b02097e9ef..199875253e 100644
--- a/packages/core/src/runtime/init.ts
+++ b/packages/core/src/runtime/init.ts
@@ -167,6 +167,7 @@ import {
 } from "./captureMotionBlur";
 import { TransportClock } from "./clock";
 import { WebAudioTransport } from "./webAudioTransport";
+import { watchAudioLoadErrors } from "./mediaLoadFailure";
 import {
   classifyWebAudioMediaRoute,
   isRouteSelectionSettled,
@@ -3601,6 +3602,7 @@ export function initSandboxRuntimeModular(): void {
   runtimeCleanupCallbacks.push(() => {
     document.removeEventListener("play", onMediaPlayWakeTransport, true);
   });
+  runtimeCleanupCallbacks.push(watchAudioLoadErrors(document));
 
   let lastVisibilityPassSeconds: number | null = null;
   const syncMediaForCurrentState = (timingRevision?: number) => {
diff --git a/packages/core/src/runtime/mediaLoadFailure.test.ts b/packages/core/src/runtime/mediaLoadFailure.test.ts
new file mode 100644
index 0000000000..2a391b1326
--- /dev/null
+++ b/packages/core/src/runtime/mediaLoadFailure.test.ts
@@ -0,0 +1,105 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { postRuntimeMessage } from "./bridge";
+import { watchAudioLoadErrors } from "./mediaLoadFailure";
+import { RUNTIME_MEDIA_LOAD_FAILED } from "./protocol";
+import { WebAudioTransport } from "./webAudioTransport";
+
+vi.mock("./bridge", () => ({ postRuntimeMessage: vi.fn() }));
+
+const posted = vi.mocked(postRuntimeMessage);
+const failures = () =>
+  posted.mock.calls
+    .map(([message]) => message)
+    .filter((m) => m.type === "diagnostic" && m.code === RUNTIME_MEDIA_LOAD_FAILED)
+    .map((m) => (m as { details: Record<string, unknown> }).details);
+
+function audio(src: string, id = "music"): HTMLAudioElement {
+  const el = document.createElement("audio");
+  el.id = id;
+  el.setAttribute("src", src);
+  return el;
+}
+
+function transport(decode: () => Promise<AudioBuffer>) {
+  const t = new WebAudioTransport();
+  (t as unknown as { _ctx: unknown })._ctx = { state: "running", decodeAudioData: vi.fn(decode) };
+  return t;
+}
+
+beforeEach(() => {
+  vi.spyOn(console, "info").mockImplementation(() => {});
+});
+
+afterEach(() => {
+  posted.mockReset();
+  vi.unstubAllGlobals();
+  vi.restoreAllMocks();
+});
+
+describe("a preview media load that fails is reported, not swallowed", () => {
+  it("a fetch the server refuses says its status, once however often playback retries", async () => {
+    vi.stubGlobal(
+      "fetch",
+      vi.fn(async () => ({ ok: false, status: 404 })),
+    );
+    const t = transport(async () => ({}) as AudioBuffer);
+    const el = audio("assets/Don't (mix).mp3");
+    await t.decodeAudioElement(el);
+    await t.decodeAudioElement(el);
+    expect(failures()).toEqual([
+      expect.objectContaining({
+        elementId: "music",
+        kind: "audio",
+        stage: "fetch",
+        code: 404,
+        extension: "mp3",
+      }),
+    ]);
+  });
+
+  it("bytes the browser cannot decode say decode and how many bytes came", async () => {
+    vi.stubGlobal(
+      "fetch",
+      vi.fn(async () => ({ ok: true, arrayBuffer: async () => new ArrayBuffer(8) })),
+    );
+    const t = transport(async () => {
+      throw new Error("unsupported codec");
+    });
+    await t.decodeAudioElement(audio("assets/song.wav"));
+    expect(failures()).toEqual([
+      expect.objectContaining({ stage: "decode", code: null, bytes: 8, extension: "wav" }),
+    ]);
+  });
+
+  it("an audio element that fails to load says its error code; a video's is left to the proxy", () => {
+    const stop = watchAudioLoadErrors(document);
+    const el = audio("assets/gone.mp3", "gone");
+    Object.defineProperty(el, "error", { value: { code: 4 } });
+    const video = document.createElement("video");
+    document.body.append(el, video);
+    el.dispatchEvent(new Event("error"));
+    video.dispatchEvent(new Event("error"));
+    stop();
+    el.dispatchEvent(new Event("error"));
+    expect(failures()).toEqual([
+      expect.objectContaining({ elementId: "gone", stage: "element", code: 4 }),
+    ]);
+    el.remove();
+    video.remove();
+  });
+  it("an audio element fed by <source> children reports when a source fails to load", () => {
+    const stop = watchAudioLoadErrors(document);
+    const el = document.createElement("audio");
+    el.id = "sourced";
+    const source = document.createElement("source");
+    source.setAttribute("src", "assets/gone.ogg");
+    el.append(source);
+    document.body.append(el);
+    source.dispatchEvent(new Event("error"));
+    stop();
+    expect(failures()).toEqual([
+      expect.objectContaining({ elementId: "sourced", stage: "element" }),
+    ]);
+    el.remove();
+  });
+});
diff --git a/packages/core/src/runtime/mediaLoadFailure.ts b/packages/core/src/runtime/mediaLoadFailure.ts
new file mode 100644
index 0000000000..b15e005658
--- /dev/null
+++ b/packages/core/src/runtime/mediaLoadFailure.ts
@@ -0,0 +1,65 @@
+import { postRuntimeMessage } from "./bridge";
+import { isAudioElement, isSourceElement } from "./domRealm";
+import { isRenderMode } from "./mediaProxy";
+import { RUNTIME_MEDIA_LOAD_FAILED, type MediaLoadStage } from "./protocol";
+import type { RuntimeJson } from "./types";
+
+const reported = new WeakMap<HTMLMediaElement, Set<MediaLoadStage>>();
+
+/** The file's extension, lower-cased, from the URL path; never its name. */
+function extensionOf(el: HTMLMediaElement): string | null {
+  const src = el.currentSrc || el.getAttribute("src") || "";
+  try {
+    const match = /\.([a-z0-9]{1,5})$/i.exec(new URL(src, document.baseURI).pathname);
+    return match?.[1]?.toLowerCase() ?? null;
+  } catch {
+    return null;
+  }
+}
+
+/** Tells the host once per element and stage that its media failed to load. `code` is the HTTP status of a fetch
+ * that answered or the element's MediaError code; `bytes` the size fetched before a decode failed. */
+export function reportMediaLoadFailure(
+  el: HTMLMediaElement,
+  stage: MediaLoadStage,
+  code: number | null,
+  bytes: number | null = null,
+): void {
+  if (isRenderMode(el)) return;
+  const stages = reported.get(el) ?? new Set<MediaLoadStage>();
+  if (stages.has(stage)) return;
+  stages.add(stage);
+  reported.set(el, stages);
+  const asset = el.getAttribute("src") ?? "";
+  const details: Record<string, RuntimeJson> = {
+    asset,
+    elementId: el.id || null,
+    kind: el.tagName.toLowerCase(),
+    stage,
+    code,
+    bytes,
+    extension: extensionOf(el),
+  };
+  postRuntimeMessage({
+    source: "hf-preview",
+    type: "diagnostic",
+    code: RUNTIME_MEDIA_LOAD_FAILED,
+    details,
+  });
+  console.info(
+    `[hyperframes] ${RUNTIME_MEDIA_LOAD_FAILED}: "${asset}" failed at ${stage}${code === null ? "" : ` (${code})`}.`,
+  );
+}
+
+/** Reports each `<audio>` that fails to load; returns the cleanup. `error` does not bubble, so this listens in capture.
+ * A `<source>` child gets the error instead of its `<audio>`.
+ * Video is left out: mediaProxy answers a video's load error with a lighter copy, so it is not yet a failure. */
+export function watchAudioLoadErrors(doc: Document): () => void {
+  const onError = (event: Event) => {
+    const target = event.target;
+    const el = isSourceElement(target) ? target.parentElement : target;
+    if (isAudioElement(el)) reportMediaLoadFailure(el, "element", el.error?.code ?? null);
+  };
+  doc.addEventListener("error", onError, true);
+  return () => doc.removeEventListener("error", onError, true);
+}
diff --git a/packages/core/src/runtime/protocol.ts b/packages/core/src/runtime/protocol.ts
index a9ddc2d3cc..cec9878800 100644
--- a/packages/core/src/runtime/protocol.ts
+++ b/packages/core/src/runtime/protocol.ts
@@ -2,6 +2,8 @@ export const RUNTIME_PROTOCOL_VERSION = 1 as const;
 
 export const RUNTIME_FILLER = "hf-runtime-filler";
 
+export const RUNTIME_MEDIA_LOAD_FAILED = "runtime_media_load_failed";
+
 export const RUNTIME_PROTOCOL_CAPABILITIES = [
   "seconds-time",
   "rational-fps",
@@ -106,3 +108,33 @@ export function inspectRuntimeProtocol(value: unknown, legacyFps = 30): RuntimeP
     metadata: message as RuntimeProtocolV1,
   };
 }
+
+const STAGES = ["fetch", "decode", "element"] as const;
+export type MediaLoadStage = (typeof STAGES)[number];
+
+export interface MediaLoadFailure {
+  elementId: string | null;
+  kind: string;
+  stage: MediaLoadStage;
+  code: number | null;
+  bytes: number | null;
+  extension: string | null;
+}
+
+const numberOrNull = (n: unknown) => (typeof n === "number" ? n : null);
+const stringOrNull = (s: unknown) => (typeof s === "string" ? s : null);
+
+export function parseMediaLoadFailure(value: unknown): MediaLoadFailure | null {
+  if (typeof value !== "object" || value === null) return null;
+  const { elementId, kind, stage, code, bytes, extension } = value as Record<string, unknown>;
+  const known = STAGES.find((s) => s === stage);
+  if (!known || typeof kind !== "string") return null;
+  return {
+    elementId: stringOrNull(elementId),
+    kind,
+    stage: known,
+    code: numberOrNull(code),
+    bytes: numberOrNull(bytes),
+    extension: stringOrNull(extension),
+  };
+}
diff --git a/packages/core/src/runtime/webAudioTransport.test.ts b/packages/core/src/runtime/webAudioTransport.test.ts
index fbd0555c36..6df4424416 100644
--- a/packages/core/src/runtime/webAudioTransport.test.ts
+++ b/packages/core/src/runtime/webAudioTransport.test.ts
@@ -1776,6 +1776,7 @@ describe("WebAudioTransport", () => {
     }
     const el = (src: string) =>
       ({
+        tagName: "AUDIO",
         getAttribute: (name: string) => (name === "src" ? src : null),
         currentSrc: "",
       }) as unknown as HTMLMediaElement;
diff --git a/packages/core/src/runtime/webAudioTransport.ts b/packages/core/src/runtime/webAudioTransport.ts
index e662807db9..d123820f13 100644
--- a/packages/core/src/runtime/webAudioTransport.ts
+++ b/packages/core/src/runtime/webAudioTransport.ts
@@ -14,6 +14,7 @@ import {
   resolveMasterBusElement,
 } from "../audioGroups.js";
 import { swallow } from "./diagnostics";
+import { reportMediaLoadFailure } from "./mediaLoadFailure";
 import { createLevelTap, type LevelTap, type StereoLevel } from "./levelTap.js";
 import { clampAudioGain } from "../audioGain.js";
 import { getDebugSurface } from "./globals.js";
@@ -355,12 +356,12 @@ export class WebAudioTransport {
     if (!src) return Promise.resolve(null);
     const pending = this._decoding.get(src);
     if (pending) return pending;
-    const decoding = this.fetchAndDecode(src).finally(() => this._decoding.delete(src));
+    const decoding = this.fetchAndDecode(src, el).finally(() => this._decoding.delete(src));
     this._decoding.set(src, decoding);
     return decoding;
   }
 
-  private async fetchAndDecode(src: string): Promise<AudioBuffer | null> {
+  private async fetchAndDecode(src: string, el: HTMLMediaElement): Promise<AudioBuffer | null> {
     if (this._bufferCache.has(src)) return this._bufferCache.get(src)!;
     if (this._failedSrcs.has(src)) return null;
     if (!this._ctx) return null;
@@ -378,11 +379,13 @@ export class WebAudioTransport {
       const response = await fetch(src, { cache: "no-store" });
       if (!response.ok) {
         swallow("webAudioTransport.fetch", new Error(`${response.status} ${src}`));
+        reportMediaLoadFailure(el, "fetch", response.status);
         return null;
       }
       arrayBuffer = await response.arrayBuffer();
     } catch (err) {
       swallow("webAudioTransport.fetch", err);
+      reportMediaLoadFailure(el, "fetch", null);
       return null;
     }
 
@@ -396,6 +399,7 @@ export class WebAudioTransport {
     } catch (err) {
       this._failedSrcs.add(src);
       swallow("webAudioTransport.decode", err);
+      reportMediaLoadFailure(el, "decode", null, arrayBuffer.byteLength);
       return null;
     }
   }
diff --git a/packages/studio/src/player/hooks/previewMessageRouter.test.ts b/packages/studio/src/player/hooks/previewMessageRouter.test.ts
index 2b16c4b090..2c8480c78b 100644
--- a/packages/studio/src/player/hooks/previewMessageRouter.test.ts
+++ b/packages/studio/src/player/hooks/previewMessageRouter.test.ts
@@ -128,6 +128,46 @@ describe("preview quality messages", () => {
     expect(usePlayerStore.getState().previewFacts).toBeNull();
   });
 
+  it("keeps each failed media load the preview reports, and ignores other diagnostics", () => {
+    const details = {
+      asset: "assets/x.mp3",
+      elementId: "music",
+      kind: "audio",
+      stage: "decode",
+      code: null,
+      bytes: 8,
+      extension: "mp3",
+    };
+    routeMessage({
+      source: "hf-preview",
+      type: "diagnostic",
+      code: "runtime_media_load_failed",
+      details,
+    });
+    expect(usePlayerStore.getState().mediaLoadFailure).toEqual({
+      elementId: "music",
+      kind: "audio",
+      stage: "decode",
+      code: null,
+      bytes: 8,
+      extension: "mp3",
+    });
+    const kept = usePlayerStore.getState().mediaLoadFailure;
+    routeMessage({
+      source: "hf-preview",
+      type: "diagnostic",
+      code: "runtime_web_audio_bypass",
+      details,
+    });
+    routeMessage({
+      source: "hf-preview",
+      type: "diagnostic",
+      code: "runtime_media_load_failed",
+      details: { ...details, stage: "?" },
+    });
+    expect(usePlayerStore.getState().mediaLoadFailure).toBe(kept);
+  });
+
   it("sends the chosen quality to a preview that has just loaded", () => {
     usePlayerStore.getState().setPreviewQuality(0.25);
     const postMessage = vi.fn();
diff --git a/packages/studio/src/player/hooks/previewMessageRouter.ts b/packages/studio/src/player/hooks/previewMessageRouter.ts
index d9215404c3..88cb80a40f 100644
--- a/packages/studio/src/player/hooks/previewMessageRouter.ts
+++ b/packages/studio/src/player/hooks/previewMessageRouter.ts
@@ -13,6 +13,10 @@ import { usePlayerStore, type TimelineElement } from "../store/playerStore";
 import type { ClipManifestClip, IframeWindow, PlaybackAdapter } from "../lib/playbackTypes";
 import { hasTimelinePerformanceFixtureLease } from "../lib/timelinePerformanceFixture";
 import { acceptStudioRuntimeMessage, postRuntimeControlMessage } from "../lib/runtimeProtocol";
+import {
+  parseMediaLoadFailure,
+  RUNTIME_MEDIA_LOAD_FAILED,
+} from "@hyperframes/core/runtime/protocol";
 import {
   parsePlaybackHealth,
   parsePreviewCopies,
@@ -38,6 +42,8 @@ interface PreviewMessage {
   copies?: unknown;
   health?: unknown;
   facts?: unknown;
+  code?: unknown;
+  details?: unknown;
 }
 
 export interface PreviewMessageRouterDeps {
@@ -136,6 +142,12 @@ function applyStoreReport(data: PreviewMessage): boolean {
     case "preview-facts":
       store.setPreviewFacts(parsePreviewFacts(data.facts));
       return true;
+    case "diagnostic": {
+      if (data.code !== RUNTIME_MEDIA_LOAD_FAILED) return false;
+      const failure = parseMediaLoadFailure(data.details);
+      if (failure) store.setMediaLoadFailure(failure);
+      return true;
+    }
     default:
       return false;
   }
diff --git a/packages/studio/src/player/store/previewQualitySlice.ts b/packages/studio/src/player/store/previewQualitySlice.ts
index 21a6ebc7dd..0f9c77da60 100644
--- a/packages/studio/src/player/store/previewQualitySlice.ts
+++ b/packages/studio/src/player/store/previewQualitySlice.ts
@@ -1,5 +1,6 @@
 import type { StoreApi } from "zustand";
 import { isPreviewQuality, type PreviewQuality } from "@hyperframes/core/preview-quality";
+import type { MediaLoadFailure } from "@hyperframes/core/runtime/protocol";
 import { readStudioUiPreferences, writeStudioUiPreferences } from "../../utils/studioUiPreferences";
 
 /** The lighter copies of heavy videos the preview wants at its current quality. */
@@ -53,6 +54,8 @@ export interface PreviewQualitySlice {
   setPlaybackHealth: (health: PlaybackHealth | null) => void;
   previewFacts: PreviewFacts | null;
   setPreviewFacts: (facts: PreviewFacts | null) => void;
+  mediaLoadFailure: MediaLoadFailure | null;
+  setMediaLoadFailure: (failure: MediaLoadFailure | null) => void;
   /** Bumped by requestPreviewFacts; the preview owner forwards each bump and the answer lands in previewFacts. */
   previewFactsRequests: number;
   requestPreviewFacts: () => void;
@@ -87,6 +90,8 @@ export function createPreviewQualitySlice(
     setPlaybackHealth: (playbackHealth) => set({ playbackHealth }),
     previewFacts: null,
     setPreviewFacts: (previewFacts) => set({ previewFacts }),
+    mediaLoadFailure: null,
+    setMediaLoadFailure: (mediaLoadFailure) => set({ mediaLoadFailure }),
     previewFactsRequests: 0,
     requestPreviewFacts: () =>
       set((state) => ({ previewFactsRequests: state.previewFactsRequests + 1 })),