The error message, "Table is already locked" is returned when attempting to grant privileges using the privileges dialog box on a feature class added to the map by a user with privileges on it in ArcGIS Pro.

Workaround

In the case that granting partial privileges is required (a subset of insert/update/delete) and the grantee already has the class open, work with an administrator to temporarily disconnect the user, while privileges are granted (or direct communication with the grantee). If full privileges are being granted no additional actions are required.

Steps to Reproduce