When attempting to create a relationship class where the connected user does not own both the origin and destination tables or feature classes, the following error message is displayed:
Error: Failed to create the specific relationship class. Must be the owner to perform this operation.
As of ArcGIS 10, the geodatabase no longer allows the creation of relationship classes between tables or feature classes not owned by the connected user. This also applies to the creation of feature-linked annotation and attachments, both of which use relationship classes.
This change was made in order to block the ability for one user to create a relationship class using a table/feature class owned by another user. This action could, in turn, prevent other users from accessing the feature class in question, since they do not have permissions on the related data.
To create a relationship class, both the origin and destination tables/feature classes must be owned by the same user.