How to prevent concurrent update attachments

[g]

In our team we've already had several times an attachment updated by person A and updated by person B, where the updates form person A were disapeared. It seems that A and B can open the same attachment and save the document where only the updates by the person who saved the attachment last remain.

What does Confluence offer to prevent this?

[Nic Brough -Adaptavist-]

Natively, nothing, and technically, it can't anyway.

It doesn't "know" that more than one person is editing a file on another machine.  There are some add-ons in the marketplace that implement locking, so you can flag an attachment as under edit by another user and prevent people using them, but there is no way to prevent two users downloading a document and working concurrently.  Even the best locking system can't stop it happening, just warn people that someone else might be working on it.

[María Fernández Castro]

In document and code source management there is the concept of check in and check out that could be implemented. And if you don't download the document, but edit it in the server, the system should be able to notice there are two or more people in this situation. I wouldn't say there is no way to prevent that. Simply that it's not natively implemented.