Deleting a project completely removes the record, which cannot be undone. For data integrity and proper auditing, some items cannot be removed. If the action is not permitted, the Delete Project button will be greyed out.
You can delete a project as long as there are no pending or paid invoices associated with the project. If you already issued an invoice, it can be canceled as long as you have not collected a payment yet. Once there are no pending or paid invoices, you will be able to delete the project.