000511: Unable to get a schema lock for <value>.


To modify the alias of a feature class, the Set CAD Alias tool creates a schema lock so that it can modify the alias of the field. If the tool cannot acquire a schema lock to allow editing of the field, this error occurs.


Another user or application has created a schema lock, which prevents the tool from creating one. Close the other application pointing to the feature class, or ensure that another user is not accessing the data.