OS: Windows 7 64-bit Firefox ver: Firefox Quantum 64.0.2 (64-bit) Lately Firefox has been randomly restarting itself and when it did my antivirus (Avast!) displayed this error message that says: "RunDLL - Error in C:\Program Files\AVAST Software\Avast\defs\19011102\bcuengine.dll Missing entry: _CloseBrowser@16 " I don't know the connection between Firefox and Avast but this problem is giving me a lot of inconvenience.