Checking Firefox version using cmd returns an error

Question

On checking the version of Firefox using firefox -v, I get the following error.

(process:12746): GLib-CRITICAL **: g_slice_set_config: assertion 'sys_page_size == 0' failed
Mozilla Firefox 31.0

I am running some Selenium tests on the remote machine using Firefox drivers. It might be a novice question, for which I apologize. What could be reason to get this error, even though it tells the Firefox version. On running the tests, I get the same issue.

17:23:38.849 WARN - Exception: Unable to connect to host 127.0.0.1 on port 7055 after 45000 ms.     
Firefox console output:

(process:12667): GLib-CRITICAL **: g_slice_set_config: assertion 'sys_page_size == 0' failed
Error: no display specified

(process:12674): GLib-CRITICAL **: g_slice_set_config: assertion 'sys_page_size == 0' failed
Error: no display specified

It seems like these two are related. Or is it due to the size of the window set to 0?

Answer 1

After researching on this issue for over 4 hrs, I found that this ff was being launched on a headless ubuntu. I tried the following on the cmd prompt.

Install Xvfb – the X Virtual FrameBuffer ( It was already installed )

"The above piece of software emulates the framebuffer using virtual memory which lets you run X-Server in machines with no display devices. This service is required to make browsers run normally by making them believe there is a display available."

export DISPLAY=:10 firefox

It worked like a charm after this. It was related to a config for headless machine to be able to launch ff without display. Please do refer the following post which was really helpful and credit goes to him for saving me another 4-5 hrs.

http://www.installationpage.com/selenium/how-to-run-selenium-headless-firefox-in-ubuntu/