I have an external drive with financial/tax records. For security, I encrypted it. But when I mount the disk, I'm not asked to confirm password.

I went to Keychain Access, and, sure enough, the password is stored there (perhaps I approved this accidentally). So I chose "delete" for that item, but it won't delete.

A few processes are permitted to access this keychain item; perhaps that's why I can't delete it. They are: APFSUserAgent, CSUserAgent, and APFSUserAgent (yes, a repeat).

Any ideas?