Product Firefox Release Channel release Version 49.0.2 Build ID 20161019084923 OS Windows 10 OS Version 10.0.14393 Signature: _copysign KERNELBASE.dll = Microsoft combase.dll = Microsoft ntdll.dll = Microsoft -------------------------- Perform a System File Check to fix corrupted system files Win 7, 8, 10, Vista: https://support.microsoft.com/en-us/kb/929833 Win XP: https://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/system_file_checker.mspx?mfr=true See if there are updates for your graphics drivers https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration