Dropbox has confirmed that a bug with it's Selective Sync feature has deleted some of its user's files. The feature, which limits cloud syncing by downloading selected folders to a local server, has been the cause of years worth of files being lost among the cloud storage service's users.
In e-mails to users, the file hosting service says the issue "affected a small number" of users, but added that affected users will receive a year of Dropbox Pro and a personalized link to any recovered documents.
According to Dropbox, the deletion of files occurred when the desktop client was either powered down or restarted as the user was applying the Selective Sync settings.
Dropbox says it is forcing users to update their desktop application to its most recent version, which has been updated to patch the error.
The bottom line is the 3-2-1 rule of data backup should be remembered: three copies with two different formats and one off-site backup.