I have an enterprise geodatabase with about 20 users. Each user has a corresponding schema. When in Arc Catalog, if only the owned schema box is checked in SQL Management studio I receive a permissions error in Catalog. However, if both the owned/default schema are selected in addition to the SDE schema, then I have no problem, importing/previewing data.
Additionally, even if SDE is chosen, it grays out, but later becomes un-checked somehow.
For database permissions I have selected create procedure, table, view, and connect. Roles for each user are configured in SQL Management Studio as db_datawriter.
I am using ArcGIS 10.2.1/SQL Server 2008 R2