diff --git a/cli/engine/engines/browser/detect-url.mjs b/cli/engine/engines/browser/detect-url.mjs
index c25d5d3df..5e3d5446b 100644
--- a/cli/engine/engines/browser/detect-url.mjs
+++ b/cli/engine/engines/browser/detect-url.mjs
@@ -7,6 +7,38 @@ import { profileFindingsAsync, profileStep, profileStepAsync } from '../../profi
 import { captureVisualContrastCandidate } from '../visual/screenshot-contrast.mjs';
 import { checkContentHiddenAtRest } from '../../rules/checks.mjs';
 
+// On Windows, puppeteer's bundled Chrome lives in a user-writable cache
+// directory. Its GPU process can be denied (STATUS_ACCESS_DENIED) by security
+// software or the GPU sandbox because it launches from an untrusted path.
+// Chrome then crash-loops the GPU process, and each relaunch briefly flashes a
+// compositor surface, the black window users report during `detect <url>`
+// (issue #372). The system-installed Chrome runs from a trusted location with a
+// healthy GPU, so channel:'chrome' avoids the crash entirely; both use hardware
+// GPU, so contrast measurement is unaffected. Scope this to Windows only: other
+// platforms do not have the bug, so they keep the pinned bundled build for
+// consistent measurement across machines. Fall back to bundled when the switch
+// fails (Chrome not installed, or channel resolution fails). If the bundled
+// launch then also fails, surface the original system-Chrome error as the
+// cause so the real failure is not lost.
+async function launchBrowser(puppeteer, { headless = true, args = [] } = {}) {
+  let channelError;
+  if (process.platform === 'win32') {
+    try {
+      return await puppeteer.default.launch({ channel: 'chrome', headless, args });
+    } catch (err) {
+      // System Chrome unavailable or unlaunchable; fall through to the bundled
+      // browser, but keep the error in case the fallback fails too.
+      channelError = err;
+    }
+  }
+  try {
+    return await puppeteer.default.launch({ headless, args });
+  } catch (err) {
+    if (channelError && err && err.cause === undefined) err.cause = channelError;
+    throw err;
+  }
+}
+
 // Reveal sweep + invisible-text measurement for the content-hidden-at-rest
 // rule. Scrolls through the document with instant jumps (bypasses CSS
 // scroll-behavior: smooth) so IntersectionObserver / scroll reveal handlers
@@ -178,7 +210,7 @@ async function detectUrl(url, options = {}) {
     phase: 'load',
     ruleId: 'launch-browser',
     target: url,
-  }, () => puppeteer.default.launch({ headless: true, args: launchArgs }));
+  }, () => launchBrowser(puppeteer, { headless: options?.headless ?? true, args: launchArgs }));
   const page = await profileStepAsync(profile, {
     engine: 'browser',
     phase: 'load',
@@ -312,7 +344,7 @@ async function createBrowserDetector(options = {}) {
     throw new Error('puppeteer is required for URL scanning. Install: npm install puppeteer');
   }
   const launchArgs = options.launchArgs || (process.env.CI ? ['--no-sandbox', '--disable-setuid-sandbox'] : []);
-  const browser = options.browser || await puppeteer.default.launch({
+  const browser = options.browser || await launchBrowser(puppeteer, {
     headless: options.headless ?? true,
     args: launchArgs,
   });
@@ -337,4 +369,4 @@ async function createBrowserDetector(options = {}) {
   };
 }
 
-export { runVisualContrastFallback, detectUrl, createBrowserDetector };
+export { runVisualContrastFallback, detectUrl, createBrowserDetector, launchBrowser };
diff --git a/scripts/test-suites.mjs b/scripts/test-suites.mjs
index d8ef865bd..0c51a6bff 100644
--- a/scripts/test-suites.mjs
+++ b/scripts/test-suites.mjs
@@ -87,13 +87,14 @@ export const SUITES = {
       /^scripts\/(benchmark-detector|build-browser-detector|build-extension)\.js$/,
       /^site\/(pages\/detector|public\/antipattern|data\/anti-patterns-catalog\.js)/,
       /^tests\/design-system\.test\.mjs$/,
-      /^tests\/(detect-antipatterns|detect-cli-design-contamination|inline-ignores|extension-build|fixtures\/antipatterns)/,
+      /^tests\/(detect-antipatterns|detect-cli-design-contamination|detect-url-launch|inline-ignores|extension-build|fixtures\/antipatterns)/,
     ],
     commands: [
       {
         runner: 'bun',
         files: [
           'tests/detect-antipatterns.test.js',
+          'tests/detect-url-launch.test.mjs',
           'tests/inline-ignores.test.mjs',
           'tests/lib/detector-bundle.test.js',
         ],
diff --git a/tests/detect-url-launch.test.mjs b/tests/detect-url-launch.test.mjs
new file mode 100644
index 000000000..53a147722
--- /dev/null
+++ b/tests/detect-url-launch.test.mjs
@@ -0,0 +1,81 @@
+import { describe, test, expect, afterEach } from 'bun:test';
+import { launchBrowser } from '../cli/engine/engines/browser/detect-url.mjs';
+
+// launchBrowser prefers the system-installed Chrome on Windows to dodge the
+// bundled-Chrome GPU crash-loop (issue #372), and keeps the pinned bundled
+// build everywhere else. The function takes the puppeteer module as a
+// parameter, so a fake lets us assert the launch strategy without a real
+// browser or a real OS.
+
+const realPlatform = Object.getOwnPropertyDescriptor(process, 'platform');
+
+function setPlatform(value) {
+  Object.defineProperty(process, 'platform', { value, configurable: true });
+}
+
+afterEach(() => {
+  Object.defineProperty(process, 'platform', realPlatform);
+});
+
+function makePuppeteer({ failChannel = false } = {}) {
+  const calls = [];
+  const fakeBrowser = { __fake: true };
+  return {
+    calls,
+    fakeBrowser,
+    mod: {
+      default: {
+        async launch(opts) {
+          calls.push(opts);
+          if (failChannel && opts.channel === 'chrome') {
+            throw new Error('Could not find Chrome (channel: chrome)');
+          }
+          return fakeBrowser;
+        },
+      },
+    },
+  };
+}
+
+describe('launchBrowser', () => {
+  test('Windows: prefers system Chrome via channel:chrome', async () => {
+    setPlatform('win32');
+    const p = makePuppeteer();
+    const browser = await launchBrowser(p.mod, { headless: true, args: ['--foo'] });
+
+    expect(browser).toBe(p.fakeBrowser);
+    expect(p.calls).toHaveLength(1);
+    expect(p.calls[0].channel).toBe('chrome');
+    expect(p.calls[0].headless).toBe(true);
+    expect(p.calls[0].args).toEqual(['--foo']);
+  });
+
+  test('Windows: falls back to bundled when system Chrome is unavailable', async () => {
+    setPlatform('win32');
+    const p = makePuppeteer({ failChannel: true });
+    const browser = await launchBrowser(p.mod, { headless: true, args: [] });
+
+    expect(browser).toBe(p.fakeBrowser);
+    expect(p.calls).toHaveLength(2);
+    expect(p.calls[0].channel).toBe('chrome'); // first attempt
+    expect(p.calls[1].channel).toBeUndefined(); // fallback: bundled, no channel
+  });
+
+  test('non-Windows: uses bundled Chrome directly, no channel', async () => {
+    setPlatform('linux');
+    const p = makePuppeteer();
+    const browser = await launchBrowser(p.mod, { headless: true, args: [] });
+
+    expect(browser).toBe(p.fakeBrowser);
+    expect(p.calls).toHaveLength(1);
+    expect(p.calls[0].channel).toBeUndefined();
+  });
+
+  test('non-Windows: never attempts channel:chrome even if it would succeed', async () => {
+    setPlatform('darwin');
+    const p = makePuppeteer();
+    await launchBrowser(p.mod, {});
+
+    expect(p.calls.every(c => c.channel === undefined)).toBe(true);
+  });
+});