Dropbox has disabled old shared document links in a bid to prevent its users' files from being accessed by unintended recipients. Before the change, anyone in possession of a Dropbox shared document link could access the file it pointed to, but the documents were inaccessible to those without the link, a form of security through obscurity. That poses no problems when users know who has the link, but there are a number of unexpected ways that information can fall into other hands, prompting Dropbox to disable links shared before May 5.