Can we upload email IDs to populate Users in Record Permission fields? We have few duplicate First Name-Last Name user scenarios which are being fetched using a Data Query Transporter feed & email IDs are the only unique attributes available in a column.
You cannot use email directly. You need to use either username or numeric ID of the user.
But in DataFeed Source tab, you can create a field with Lookup function, given you have populated your users into Contacts application for example.
David Petty explained it in here: