if your Mac keeps asking for the login keychain password
The password of your macOS user account might not match the password of your login keychain. Either create a new login keychain or update it with your new password.
If you need to update your keychain password on Mac
By default, your keychain password is the same as your user password (the password you use to log in to the computer). If you change the user password in Users & Groups preferences, the keychain password is automatically changed to match it. If your user password is changed by an administrator, your keychain password may not be changed automatically, and you’re asked to enter the keychain password the next time you log in. You can update the keychain password to match your new user password. To unlock your keychain and change the password, you must know the current keychain password (which is usually the same as the previous user password).
Change your keychain password to match your user password
- In the Keychain Access app
on your Mac, click “login” in the Keychains list. - Choose Edit > Change Password for Keychain “login.”
- If the keychain is locked, enter the previous user password for the computer, then click OK.
- If you entered the correct password, a new window appears.
- Enter the previous user password again in the Current Password field.
- Enter your new user password in the New Password field.
- Reenter the new user password in the Verify field, then click OK.
If you need to update your keychain password on Mac - Apple Support