I use dropbox on ipad and 2 Mac's essentially for the app Scrivener.
I saw last week that all my scrivener projects'size (it is packages = folders) was 0 byte.
on my macbook they still had the correct size (a chance as since I trust dropbox I don't make backups of my dropbox folder, I know it's terrible)
but the sync is not correcting the problem: the scrivener projects stay at 0 byte while they have the correct size on my macbook and I have "everything is synced).
On my iPad and my other mac they are at 0 bytes
I re-installed dropbox.. but still the same