I have been using Firefox with several tabs active. I close all of the tabs and close Firefox. When I try to restart Firefox I get the following message: Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system. I go to System/Administration/System Monitor and I find the following entry: Process Name Status % CPU Nice ID Memory Waiting Channel firefox-bin Sleeping 0 0 3391 39.4 MiB futex_wait_que_me Even before I click OK on the Firefox is already ... message a new firefox-bin process is started. When I select a firefox-bin process on the System Monitor the End Process button is activated. When I click that button all of the firefox-bin processes are ended and I can open the Firefox browser. Why am I getting the futex_wait_que_me Waiting Channel for the firefox-bin process and how do I avoid it? I am using Firefox version 3.6.23, Mozilla Firefox for Ubuntu canonical - 1.0, with Ubuntu 10.04 Thanks, Dan Healy