Q: I have had problems with the keychain access since downloading OSX to my macbook. Never had a keychain password but now it will not let me unlock or get into  my computer with out the Keychain passwords.

What about when you get this error: "UNIX[Invalid argument]" when trying to reset the keychain?

Don't know about you, but same issue here (late 2012 iMac... not that it matters). Keeps asking for the password for the "login" keychain; I tried restoring it but in the Keychain Access app, the login keychain shows (empty and) read-only.

When I try to restore my default keychain (from within Keychain Access' preferences) I get the same "UNIX[invalid argument]" message.

The problem started to appear without an apparent reason in the middle of a Yosemite session, and problem won't disappear. Maybe later I'll try to revert to a TM backup.

The solution by cgiordano in I forgot my Keychain Password. As I follow the steps, after clicking ""Reset to my default Keychain""a new window showing ""UNIX[Invalid argument]"". Give me a solution to reset my Keychain Password. works for me. Good!