selenium TimeoutException: timed out receiving message from renderer

TL;DR

Chrome stopped answering Selenium's commands, usually because a navigation never finished (a pending request, a download dialog, or an unload handler hanging). Do not just raise the timeout; set an explicit page-load timeout and a less strict load strategy so one stuck resource cannot hang the whole session.

Error

selenium.common.exceptions.TimeoutException: Message: timeout: Timed out receiving message from renderer: 300.000

Steps

1. Set an explicit page-load timeout so it fails fast instead of hanging on the default: driver.set_page_load_timeout(60) in Python, or driver.manage().timeouts().pageLoadTimeout(Duration.ofSeconds(60)) in Java. Expected: slow pages raise TimeoutException at 60s with a clear stack.
2. Switch the page-load strategy to eager so Selenium returns after DOM content loads: set pageLoadStrategy: 'eager' in Chrome options. Expected: navigations return before slow subresources finish.
3. Replace implicit waits with explicit ones: WebDriverWait(driver, 10).until(EC.presence_of_element_located((By.ID, "app"))). Expected: waits target the element you need, not the renderer.
4. Check for renderer blockers: file-download dialogs, beforeunload handlers, or pages opening print preview. Expected: removing or handling the blocker stops the hang.
5. In headless CI add --disable-dev-shm-usage to Chrome options (tiny shared memory crashes the renderer). Expected: renderer crashes disappear.

When to use

• The error message mentions the renderer.
• It happens on driver.get or on a click that triggers navigation.
• It is flaky in Docker but fine on your laptop.

When not to use

• NoSuchElementException (the page loaded; the selector is wrong).
• SessionNotCreatedException (driver and browser versions disagree).
• Timeouts in your own test code rather than in Selenium calls.

Tool compatibility

• Selenium 4.x in Python, Java, or JavaScript bindings.
• Chrome and Chromedriver 110 and newer.

Variant phrasings

Timed out receiving message from renderer: 10.000

A script timeout, not a page load: some JavaScript ran past the script timeout. Raise it or fix the script.

only in headless

Missing flags or a resource limit in the container. Start with --disable-dev-shm-usage.

right after a file download starts

The download dialog blocks the renderer. Set a default download directory so no dialog appears.

Why it happens

Selenium talks to Chrome over the DevTools protocol; if the renderer is stuck (an infinite unload handler, a huge page, a tab crashed from shared-memory exhaustion), commands queue with no reply until the timeout fires.

Edge cases

• pageLoadStrategy: 'none' returns immediately, but then every later command needs its own explicit wait.
• Raising the renderer timeout without fixing the cause just moves the hang later.
• Downloads need a preset download directory, otherwise the dialog blocks the renderer every time.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_Jp8BetKYL4f04QaEApvCpA