This feature, along with Portal Pages, Channels, and non-SAIL interfaces, has been deprecated and will be removed in a future release of Appian.
See Support for Application Portal and non-SAIL forms for more information.
The concept of user-based storage quotas is irrelevant in modern environments. In a future release of Appian we will be removing user-based storage limits.
For information about the User Storage Space Quotas [Deprecated], see the Appian 16.2 documentation.