We have a one week old iMac (21 inch model) using the latest OS and are continually getting asked "mail (or iCloud helper exe or address book etc..) wants to use your keychain login … please enter password" even though we have never set up keychain or a login password etc… It may have started after sync with iPad / iPhone. If we press "accept" then it's happy for a while but next time the same message, endless times a day. If we press "cancel" the request comes up repeatedly, then gives up, and then returns again later.
