macOS Sierra: A keychain cannot be found

According to this article : Keychain Access: If you’re asked frequently to unlock your keychain

If you don’t remember your previous user password

If you don’t remember your previous user password, you need to reset your default keychain. Resetting the default keychain deletes all the passwords saved in the keychain, but should allow you to sync up.

1. Choose Keychain Access > Preferences, then click General.
2. Click Reset My Default Keychain.
3. In the Finder, choose Apple menu > Log Out. When you log in again, save your current password in a keychain.

A screen shot taken from the link posted by sberman , why doesn't it work ? the method posted by me and screen shot are almost same .

The same question is answered here:

A Keychain cannot be found

Keychain Issues - Resolve see post by Kappy

I have the same problem and I found the solution in : A keychain cannot be found alert whenever I boot up my macbook ??

It works for me.