Browsing context has been discarded using GeckoDriver Firefox through Selenium

Question

I didn't make any changes to my python selenium program and it worked fine 3 days ago. Now when i try to use it i get:

Browsing context has been discarded Failed to decode response from marionette

Any idea what could have caused this outside the code? (since no changes were made)

I'm using firefox and geckodriver. After i got these errors i updated firefox, geckodriver, and selenium, but it didn't help.

Answer 1

I experienced the same error on a particular site, after performing a successful login and when I was redirected to the next page.

While Inspecting the source of the new page code in my Firefox browser, I noticed some bad format/HTML quality details that went away after a manual refresh. (I suspect related to lack of quality of that site in particular).

What I did in order to remediate this was to start every next step on a new page with a refresh on my driver:

def my_next_step(driver):
    driver.refresh()
    time.sleep(10)
    element=driver.switch_to_frame('iframe')
    # .......

This helped me overcome the site quality issues.

Answer 2

On Ubuntu 22.10 using (apt, not snap) Firefox and Selenium in Python I also got this error after:

driver.switch_to.alert.accept()

The solution for me was to switch back to the context with:

def upload_file(driver, filepath):
    """Uploads a Ublock Origin backup (template) .txt file into the Ublock
    Origin extension."""
    driver.find_element("id", "restoreFilePicker").send_keys(filepath)
    time.sleep(1)
    driver.switch_to.alert.accept()
    time.sleep(1)
    # Switch back to first tab (and reload/restore it).
    new_window = driver.window_handles[0]
    driver.switch_to.window(new_window)

This answer was given in this question.

Answer 3

I removed size of window it is working without this error

Answer 4

This error message...

Browsing context has been discarded
.
Failed to decode response from marionette

...implies that the communication between GeckoDriver and Marionette was broken.

Some more information regarding the binary version interms of:

• Selenium Server/Client
• GeckoDriver
• Firefox

Additionally, your code block and the error stack trace would have given us some clues about whats wrong happening. However this issue can happen due to multiple factors as follows:

• As per Hang when navigation request removes the current browsing context if you have used driver.navigate().back(); when Selenium's focus was within an <iframe> this error is observed.
• As per Crash during command execution results in "Internal Server Error: Failed to decode response from marionette" this issue can also occur due to ctypes checks for NULL pointer derefs.
  • You can find the Selenium testcase here. Perhaps instead of panicking, it would have been better to handle this more gracefully by clearing any state and returning geckodriver to accept new connections again.
• As per Failed to decode response from marionette - Error to open Webdriver using python this issue can also occur if you are not using the complient version of the binaries.

GeckoDriver, Selenium and Firefox Browser compatibility chart

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Reference

You can find a relevant detailed discussion in:

• “Failed to decode response from marionette” message in Python/Firefox headless scraping script