Hi Harry, that is a message from Windows indicating that plugin-container.exe crashed. Apparently it bypassed Firefox's built-in crash detection system. The main use of plugin-container.exe is to run Flash media. Does this problem occur on sites where you are intentionally viewing Flash media such as games or some videos (most video sites do not use Flash)? If Flash seems to be running for no apparent reason, it could be due to one of your add-ons. You can view, disable, and often remove unwanted or unknown extensions on the Add-ons page. Either: * Ctrl+Shift+a (Mac: Command+Shift+a) * "3-bar" menu button (or Tools menu) > Add-ons * type or paste '''about:addons''' in the address bar and press Enter/Return In the left column of the Add-ons page, click Extensions. Then cast a critical eye over the list on the right side. Any extensions Firefox installs for built-in features are hidden from this page, so everything listed here is your choice (and your responsibility) to manage. Anything suspicious or that you just do not remember installing or why? If in doubt, disable (or remove). You also might want to try disabling extensions you can live without for 24 hours. Any improvement?