Opened Firefox. Logged into my BT Yahoo webmail. After succesful logging in I suddenly received the following message in a small popup window: ''The exception unknown software exception (0xc0000417) occured in the application at location 0x6bf0977c.'' When you click OK the window closes and so did Firefox. The crash Reporter did not open and when I checked the about:crashes to locate a crash report reference none had been created. I opened Firefox again and so far no issue, but I do not know what caused the sudden close nor why the crash reporter did not function. Any ideas thoughts etc :)