diff --git a/src/viewer/sharing/summarize-with-chatgpt.js b/src/viewer/sharing/summarize-with-chatgpt.js
index 51bd00e..55d3b95 100644
--- a/src/viewer/sharing/summarize-with-chatgpt.js
+++ b/src/viewer/sharing/summarize-with-chatgpt.js
@@ -71,8 +71,15 @@ function registerPdfTransfer(requestId, filename) {
   let awaitingAck;
   const expire = setTimeout(() => port.disconnect(), 120000);
   port.onDisconnect.addListener(() => {
+    // Chrome reports a missing receiver through lastError on disconnect.
+    // Reading it here also prevents an "Unchecked runtime.lastError" warning.
+    const disconnectError = chrome.runtime.lastError?.message;
     stopped = true;
-    if (awaitingAck) awaitingAck.reject(new Error("PDF transfer disconnected"));
+    clearTimeout(expire);
+    if (awaitingAck) {
+      awaitingAck.reject(new Error(disconnectError || "PDF transfer disconnected"));
+      awaitingAck = null;
+    }
   });
   port.onMessage.addListener((message) => {
     if (message?.type === "ack" && awaitingAck) {
diff --git a/tests/chatgpt-summary-popup.test.mjs b/tests/chatgpt-summary-popup.test.mjs
index 49731e1..ff0bc2f 100644
--- a/tests/chatgpt-summary-popup.test.mjs
+++ b/tests/chatgpt-summary-popup.test.mjs
@@ -10,6 +10,8 @@ function setup({ width = 1080, height = 1920, popupFails = false } = {}) {
   let resolveUrl;
   const listeners = new Map();
   const calls = [];
+  let onDisconnect;
+  let lastErrorReads = 0;
   const button = {
     title: "Summarize with ChatGPT",
     attributes: {},
@@ -25,10 +27,20 @@ function setup({ width = 1080, height = 1920, popupFails = false } = {}) {
     window: { screen: { availWidth: width, availHeight: height } },
     resolveDocumentReferenceUrl: () => new Promise((resolve) => { resolveUrl = resolve; }),
     chrome: {
-      runtime: { connect(options) {
-        calls.push(["connect", options]);
-        return { onMessage: { addListener() {} }, onDisconnect: { addListener() {} }, disconnect() {} };
-      } },
+      runtime: {
+        get lastError() {
+          lastErrorReads += 1;
+          return { message: "Could not establish connection. Receiving end does not exist." };
+        },
+        connect(options) {
+          calls.push(["connect", options]);
+          return {
+            onMessage: { addListener() {} },
+            onDisconnect: { addListener(listener) { onDisconnect = listener; } },
+            disconnect() {},
+          };
+        },
+      },
       windows: { async create(options) {
         calls.push(["popup", options]);
         if (popupFails) throw new Error("Popup unavailable");
@@ -46,7 +58,15 @@ function setup({ width = 1080, height = 1920, popupFails = false } = {}) {
     },
   };
   vm.runInNewContext(source, context);
-  return { click: () => listeners.get("click")(), dispatch: (event) => listeners.get(event)(), resolveUrl, calls, button };
+  return {
+    click: () => listeners.get("click")(),
+    dispatch: (event) => listeners.get(event)(),
+    resolveUrl,
+    calls,
+    button,
+    disconnect: () => onDisconnect?.(),
+    get lastErrorReads() { return lastErrorReads; },
+  };
 }
 
 test("opens the portrait popup before PDF metadata resolves, then stores the prompt before navigation", async () => {
@@ -120,3 +140,14 @@ test("local file URLs are not substituted for PDF attachments", async () => {
   assert.ok(!data.prompt.includes("file:///Users/"));
   assert.equal(fixture.calls.find(([action]) => action === "connect")[1].name, "pdf-summary-source:request");
 });
+
+test("consumes Chrome's missing-receiver error on PDF summary disconnection", async () => {
+  const fixture = setup();
+  const pendingClick = fixture.click();
+  fixture.resolveUrl("https://www.sec.gov/files/rules/other/34-16900.pdf");
+  await pendingClick;
+
+  assert.equal(fixture.lastErrorReads, 0);
+  fixture.disconnect();
+  assert.equal(fixture.lastErrorReads, 1);
+});