After talking with binary1248 he seems to have found the culpit. It's not exactly a bug in SFML, but there's still a potential fix we can try.
As for your own code, it seems like you're using some static function call or similar (global variable) to store/construct an sf::Clock object. Since the sf::Clock object will get constructed in global scope, but since the mutex inside the sf::Clock is also in a global scope and because initialization order in a global scope is undefined, it just so happens that the sf::Clock gets initialized before the mutex gets initialized, causing a crash.
So you can fix this by not having an sf::Clock constructed in the global scope.
Additionally you could try and see if
this change fixes the issue for you.
We'd actually be really glad if you could test this, since we rarely develop things on XP.