6411 Structural changes are not allowed - class is in use
Cause
This error occurs during a schema load where the loadStyle parameter has the value onlyStructuralVersioning, if you attempt to change a class (for example, by adding a control to a form) and the class has no persistent instances but is in use at the time (for example, the form could be running).
Action
Retry the schema load when the class is not in use.
