Q:

Unable to access SFDC User Objects "EmailPreferencesAutoBcc" entity from SOQL/SOAP interface

The entity "EmailPreferencesAutoBcc" is accessible via Tableau connection to SFDC and the entity is a standard entity for User object. 
When Accessed via SOQL on SOAP interface the following Error is throw. 
No such column 'EmailPreferencesAutoBcc' on entity 'User'. 

This is the corresponding SOQL i'm using:
select EmailPreferencesAutoBcc from User limit 10

A:

You should check that User, which you use for SOAP call, has permission to Read this field. 
Check Set Field Permissions in Permission Sets and Profiles to find out where to check permissions.