User Agent: Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:49.0) Gecko/20100101 Firefox/49.0 Build ID: 20160922200204 Steps to reproduce: Could you please solve this problem? The problem is in the source code of firefox: https://github.com/mozilla/geckodriver/issues/181

Not reproducible.

As described on the geckodriver issue, I can see leakage more or less often when running debug builds. We should try to get this investigated a bit more at least, so that we can finally stop it. An example you can find here which is for e10s: https://public-artifacts.taskcluster.net/YtY3-BtYRrGsnRWxr3QxZQ/0/public/test_info//gecko.log WARNING: YOU ARE LEAKING THE WORLD (at least one JSRuntime and everything alive inside it, that is) AT JS_ShutDown TIME. FIX THIS! [Child 1213] ###!!! ASSERTION: Component Manager being held past XPCOM shutdown.: 'cnt == 0', file /home/worker/workspace/build/src/xpcom/build/XPCOMInit.cpp, line 1074 [Child 1213] WARNING: '!compMgr', file /home/worker/workspace/build/src/xpcom/glue/nsComponentManagerUtils.cpp, line 63 Leaked URLs: file:///home/worker/workspace/build/application/firefox/omni.ja file:///home/worker/workspace/build/application/firefox/browser/omni.ja x:///chrome/pdfjs/content/ file:///home/worker/workspace/build/application/firefox/omni.ja x:///modules/services-crypto/ file:///home/worker/workspace/build/application/firefox/browser/features/formautofill@mozilla.org.xpi x:///chrome/content/ file:///home/worker/workspace/build/application/firefox/omni.ja x:///chrome/toolkit/res/ file:///home/worker/workspace/build/application/firefox/omni.ja x:///modules/services-common/ chrome://browser/locale/searchplugins/ file:///home/worker/workspace/build/application/firefox/browser/omni.ja x:///chrome/devtools/modules/devtools/ file:///home/worker/workspace/build/application/firefox/omni.ja x:///modules/services-sync/ chrome://pluginproblem/content/pluginProblemBinding.css resource://gre-resources/counterstyles.css resource://gre-resources/html.css chrome://global/content/minimal-xul.css resource://gre-resources/quirk.css resource://gre/res/svg.css chrome://global/content/xul.css chrome://global/skin/scrollbars.css resource://gre-resources/number-control.css resource://gre-resources/forms.css resource://gre-resources/noscript.css resource://gre-resources/ua.css http://127.0.0.1:56373/test.html http://127.0.0.1:56373/test.html http://127.0.0.1:56373/test.html http://127.0.0.1:56373/test.html chrome://global/content/bindings/scrollbar.xml#scrollbar chrome://global/content/bindings/scrollbar.xml x:///chrome/toolkit/content/global/bindings/scrollbar.xml chrome://global/content/bindings/scrollbar.xml chrome://global/content/bindings/scrollbar.xml#thumb chrome://global/content/bindings/scrollbar.xml chrome://global/content/bindings/scrollbar.xml#scrollbar-base chrome://global/content/bindings/scrollbar.xml#scrollbar chrome://global/content/bindings/scrollbar.xml#scrollbar-base chrome://global/skin/scrollbar/slider.gif chrome://global/content/bindings/scrollbar.xml#thumb chrome://global/content/bindings/scrollbar.xml#scrollbar-base http://127.0.0.1:56373/test.html# http://127.0.0.1:56373/test.html# http://127.0.0.1:56373/test.html# chrome://global/content/platformHTMLBindings.xml#inputFields chrome://global/content/platformHTMLBindings.xml x:///chrome/toolkit/content/global/platformHTMLBindings.xml chrome://global/content/platformHTMLBindings.xml chrome://global/content/platformHTMLBindings.xml#inputFields chrome://global/content/platformHTMLBindings.xml chrome://global/content/platformHTMLBindings.xml#textAreas chrome://global/content/platformHTMLBindings.xml#browser chrome://global/content/platformHTMLBindings.xml#editor Reporter, do you see this leak for e10s (multi-process) enabled only or also when e10s is turned off in the used Firefox profile?