Selenium crashing with selenium.common.exceptions.WebDriverException: Message: newSession

I fixed the issue by updating the selenium python package and using the latest geckodriver.

Thanks @fzbd for all your help.

Additional context -

Refer to the compatibility chart here - https://firefox-source-docs.mozilla.org/testing/geckodriver/Support.html#supported-platforms

update selenium :

 pip install -U selenium

update geckodriver (choose the correct version for your needs based on the above compatibility chart)

Check the versions for all components -

firefox -vgeckodriver -Vpip freeze | grep selenium

Thanks @skyfail.Your answer helped me.The following sequence was performed and resolved the issue.

1. To upgrade selenium run: sudo pip3 install selenium --upgrade

2. To upgrade geckodriver follow steps 1-3 from this

3. sudo mv geckodriver /usr/local/bin/geckodriver , /usr/local/bin is usually in your PATH so no need to edit it.

In your log is the following line:

1540501901605 geckodriver ERROR Address in use (os error 98)

Which indicates that the driver is trying to use a port which is already used by some other process. Since the log doesn't show which port it is, you can run the driver with strace:

strace geckodriver 2>&1 | grep -iE 'bind|getsockname'

In my case I get these lines:

bind(3, {sa_family=AF_INET, sin_port=htons(4444), sin_addr=inet_addr("127.0.0.1")}, 16) = 0

getsockname(3, {sa_family=AF_INET, sin_port=htons(4444), sin_addr=inet_addr("127.0.0.1")}, [128->16]) = 0

You can then check which process is using the port (for example):

netstat -tulpn | grep -i 4444 

In my case returning:

tcp 0 0 127.0.0.1:4444 0.0.0.0:* LISTEN 31471/geckodriver

According to a issue about geckodriver port logging, you can let the os allocate a free port:

geckodriver --port 0

If all this doesn't work out, there may an incompatibility between your version of geckodriver and selenium, as this error in the log seems to suggest:

geckodriver::marionette TRACE <- [1,1,{"error":"unknown command","message":"newSession","stacktrace":"WebDriverError@chrome://marionette/content/error.js:178:5

I am using the following versions:

• firefox 62.0.3
• geckodriver 0.23.0
• selenium 3.14.1