[marlin]

According to [1], "LAN sync" only works when file has already been uploaded to the dropbox servers.

If this is accurate, then I guess this is the issue i have noticed.

1: https://superuser.com/questions/663600/set-dropbox-to-only-u...

UPDATE:

Confirmed by [2], that Dropbox LAN sync indeed only works once the file reached their servers.

"Well, when you add a file to your computer's Dropbox, the file is then synced with Dropbox servers. Dropbox will then initiate the syncing process as soon as it determines a change has been made to the file. All linked computers and shared folders will then download any new version of the file. With LAN syncing, Dropbox will look for the new file on your Local Area Network first, bypassing the need to download the file from Dropbox servers, thus speeding up the syncing process considerably."

2: https://www.dropbox.com/help/137/en

[nodata]

For anyone wondering, Dropbox changed this a while back. The requirement to sync to Dropbox first was added at that point.

[andreasvc]

That's good to know. Basically LAN sync is a misnomer, because it only works in the download direction.