Keychain "login" cannot be found to store "registrationV1"

I keep getting the following error message; Keychain "login" cannot be found to store "registrationV1"

I click on "Reset To Defaults", but it keeps coming back. There are also other, "Keychain Not Found" messages, i.e.; "Keychain "login cannot be found to store "/Users/robinson/Library/Application Support/Adobe/Acrobt/DC/Security/ES_session_storek."

Keychain "login" cannot be found to store ***@iCloud.com

It's an old Mac (iMac 24-inch, Early 2009), and it's running OS El Capitan. I've tried "Reset To Defaults"

Any suggestions would be appreciated. Thank you.

[Edited by Moderator]