if you use the icloud password to login, and later you modified the password of icloud, then the keychain will have a problem, you need to open the keychain, then right lick to delete the login keychain, and then restart to enter the new password
I have never modified anything or password. It seems that the mac mini itself will periodically lost the keychain. I just bought the mac mini six months and it's the second time it lost the keychain. It seems that it will lost keychain in every 2 months. I need to figure out the root cause. Do you have any idea?
I don't know how to delete the keychain and regenerate the new keychain, could you please teach me step by step?