Error 'Batch failed: FeatureNotEnabled: Binary field not supported' when you export related object

These fields are of the type base64 and contain the encoded file data for the File, Attachment, or Note, and cannot be exported with Bulk API enabled. If you disable Bulk API, these fields can be exported but will return only the encoding details and not the actual file uploaded into Salesforce. 

Data Loader does not support the ability to export Content and Attachments.  You can export details associated with the file, such as the Title, Owner, and Description, but the actual file itself cannot be downloaded with Data Loader.

Workaround: Use the weekly export feature to Export Backup Data from Salesforce and the files will be included.

What is Base64 data type?

Base 64-encoded binary data. Fields of this type are used for storing binary files in Attachment records, Document records, and Scontrol records. In these objects, the Body or Binary field contains the (base64 encoded) data, while the BodyLength field defines the length of the data in the Body or Binary field. In the Document object, you can specify a URL to the document instead of storing the document directly in the record.

Objects such as ContentVersions or Feed Item (Content Data field) contains binary data encoded in Base64.
While exporting such data, if "Bulk API" is enabled, we receive the error "Batch failed: FeatureNotEnabled: Binary field not supported". This is because extraction of items of type Base64 fields is not supported using bulk API.