The Yandex spider is a frequent visitor to one of the sites I manage. On occasion it replaces the page name with two ampersands and a space. So if the page is:  /mypage.aspx?param=value then it will try and crawl it as:  /&& ?param=value  Any idea why it is doing this?EDIT:If I remember correctly the IP that this mistake is coming from is based in California and not Russia. I believe that they crawl US sites from a US based IP address. Not sure if that helps.More information about the request:  IP: 199.21.99.82City: Palo AltoState: CaliforniaCountry: United StatesISP: Yandex Inc.User-Agent: Mozilla/5.0 (compatible; YandexBot/3.0; +http://yandex.com/bots)
Yandex frequently replaces page names with ampersands
web crawlers;crawl errors;yandex