Final answer:
To prevent users from accessing account records they do not own in Salesforce, the OWD sharing setting should be set to 'Private'. This restricts access to the record owner and can only be overridden by specific sharing provisions.
Step-by-step explanation:
The Organization-Wide Default (OWD) sharing setting that would need to be used to ensure that users cannot access account records that are not owned by them is 'Private'. When OWD is set to Private for the Account object, users will not be able to see each other's account records unless they are given additional permissions through Sharing Rules, Role Hierarchy, or if they are added to a Team on that record. It is a fundamental aspect of Salesforce security model that allows organizations to comply with data access policies and privacy regulations.
In Salesforce, the OWD settings control the default level of access users have to records. The 'Private' setting restricts access only to the owner of the record, ensuring that other users cannot access records they do not own.
For example, if the OWD setting for account records is set to 'Private', a user can only view and modify account records that they own. They will not have access to account records owned by other users unless they are specifically granted access.