Created attachment 8577571 [details] Screenshots from Process Hacker with details of the stuck Firefox process User Agent: Mozilla/5.0 (Windows NT 6.2; WOW64; rv:36.0) Gecko/20100101 Firefox/36.0 Build ID: 20150305021524 Steps to reproduce: I have had this issue occur repeatedly to me over the course of this week. Unfortunately I don't have any way to reproduce this issue other than browsing normally. When I have experienced this issue, I have a moderate number of tabs open. Twice it has occured when browsing a specific forum (http://www.nexusclash.com/modules.php?name=Forums) although I don't think that is the cause as it has also happened at least once without any tabs from that site open at all. Actual results: Firefox was unable to load new pages - They'd just show a white screen and act as if waiting for a response from the remote server. Each time this has happened I have verified that my internet connection is fine and I am able to load the web pages via an alternative browser. I closed Firefox. Upon trying to load up Firefox again, it complains that Firefox is already running, and gives me the option to close Firefox. Then a message pops up to say my profile is missing or inaccessible. I attempt to terminate the Firefox process in Task Manager, getting "Access Denied". I start up Process Hacker, which tells me it is unable to kill Firefox because it is in the process of terminating. I then need to reboot my laptop in order to be able to start Firefox. Expected results: Firefox should not have suddenly been unable to load new pages, it should've continued to work. Firefox should've terminated properly, so I was able to start Firefox again without needing to restart.
Firefox crashed on startup and the crash report (https://crash-stats.mozilla.com/report/index/19b9d93e-4d7e-4197-988e-4ac592150318) linked me to a related bugs that match the problem I am experiencing. Marking as duplicate =)