Revised response to: Error SQL71564: Error validating element [sql user]: The element [sql user] has been orphaned from its login
The above error causes a import of a SSMS data tier application (bacpac file) to fail. To generate such an export may have taken a significant amount of time to execute. The resolution to the issue would have been to create the required logins or delete the users and then re-export. A more friendly way of dealing with this would be to prompt during the import process. Provide the option to let the import continue and to not create any orphaned users.