If you want to reserve document numbers at the start of a project, create placeholder documents.
Placeholders act as ‘envelopes' within Aconex. You can create a placeholder at any time.
You use placeholders to reserve document numbers when you start a project. This means that a placeholder is, essentially, a set of data that a document will be attached to in the future.
See Add Placeholders. Make sure you are using the new upload experience.
If you need to update files for many documents, follow the steps to Add Documents. If an existing document number is recognized from the file name you'll see an Update label.
Alternatively you can select the documents and choose Update Documents.
Placeholder documents are usually used:
Ask the Project Administrator to check the Project Settings for your project.