When creating a Project in the NBS LCA tool, if a Project already exists with the code entered into the 'Code' field you will receive the below message:
This will prevent you for creating the project. To resolve, either choose a different code for this Project, or if the code entered is intended for this Project, locate the existing Project where this code is in use, and change that Projects code. For information on editing the details of an existing Project, please see: Editing the details of an existing Project : Support