Since I have upgraded to Mountain Lion, I have huge problems with passwords throughout the system. Although, passwords get stored into the keychain, they are not being used by almost any application or system service that I tried. Wifi keeps asking for username and password each time I change network. All websites ask for passwords, Messages App, Mail, Calendar - everything I tried. Tried removing all passwords from Keychain, they get recreated by the apps, but not used. Tried First-Aid on Keychain - nothing wrong. any ideas?