Salesforce: Inactive User

When a Salesforce user has been deactivated, can we still assign the user as the record owner, or populate the user into a lookup field? 

1. Lookup Fields

From the Page Layout (UI): In the standard Salesforce user interface, you typically cannot select or populate a lookup field with an inactive user. The UI filters out inactive users from lookup fields to prevent confusion and ensure that only active users are selectable. Therefore, if you are trying to populate a lookup field from the page layout, you will not see inactive users listed.

From the Backend: You can populate lookup fields with inactive users through backend processes. This includes using data import tools, APIs, or automated processes (like Apex code, workflows, or triggers).

2. Record Ownership

From Setup > User Interface > User Interface, look for Enable "Set Audit Fields upon Record Creation" and "Update Records with Inactive Owners" and enable it. Then, create a permission set with "Update Records with Inactive Owners" permission or enable the permission in the profile.

From the Page Layout (UI): In the standard Salesforce user interface, you typically cannot find or populate the record owner with an inactive user, even if you already have the above permission granted.

From the Backend: If you have "Update Records with Inactive Owners" permission enabled, you can populate record ownership with an inactive user through backend processes. This includes using data import tools, APIs, or automated processes (like Apex code, workflows, or triggers).

Without the permission enabled, you will receive the error message INACTIVE_OWNER_OR_USER: