Sync Pro gives you total freedom to choose what files and folders to download and how to do it. You can sync an entire folder, sync just a few files (while keeping the rest as placeholders) or you can sync nothing at all and keep the folder available for syncing in the future. Sync achieves this flexibility by giving you three synchronization modes:
Synced - this is the default state when you add a new folder. Sync copies all the files from remote peers, and automatically stays up to date with any changes, additions, and deletions.
Selective Sync - this mode just shows placeholder files in your file browser (Finder on Mac, or Windows Explorer on Windows). You can easily choose individual files or whole subfolders to sync: just right click on file/subfolder and pick "Sync to this device" option.
Disconnected - Sync won't keep any information about this folder on a device where it is set to "Disconnected," not even the names of the files. Still, folder name will be visible and you will be able to switch from Disconnected to either of the other two modes at any time in the future.
* Assuming, of course, that another device hosting the folder is online.
** IMPORTANT: Selective Sync can be switched ON/OFF in Sync Pro only.
In Sync Free on Win/Mac/Linux/WebUI Selective Sync is always OFF.
TURNING "SELECTIVE SYNC" ON/OFF
Sync gives you 3 places where syncing mode can be configured:
1. When you first connect a folder
2. After a folder is connected
3. When a folder is automatically added from one of your linked devices
Let's take a look at each of these in more detail:
1. When connecting to a folder:
When you first connect to a folder via a shared link/key, you'll see a "Selective Sync" toggle on the "Connect to folder" dialog. If you leave it OFF, this device will immediately start downloading all the content in the folder (including the full contents of any subfolders and nested folders). If you turn it ON, Sync will only receive placeholder information, which you can use to sync the full files later.
2. After the folder is already connected: using Selective Sync from the folder options menu:
Using the Selective Sync toggle for specific folders is quite convenient in situations when you have a lot of folders synced in the Selective Sync mode (that is, instead of copying all files to your disk, Sync moves only very small placeholders), but you need to sync some folders to your device in full. If these folders contain dozens of files, clicking on each and every item in order to get it copied would be a hassle. In this situation, switching "Selective Sync" OFF for a specific folder will save you time by automatically syncing 100% of data.
3. When you link your devices (using the My Devices feature):
When you link your devices, Sync will prompt one of the three synchronization modes (see above). Although this is a global setting which will apply to all the folders added on a particular linked device, it can be changed later or overriden with the Selective Sync toggle for specific folders.
Reverting to placeholders
If the files in a folder are fully synced - whether it be the result of turning placeholders into actual files or synchronizing the folder in the Synced mode from the very beginning - you can revert full files into placeholders.
If you wish to revert the whole folder, the easiest way to do so would be to turn ON 'Selective Sync' in the Folder Preferences (see above). However, if you need to convert specific files, just delete them using the appropriate contextual menu option or dragging-and-dropping them to the trash can. Once you perform this action, the actual files will be deleted and immediately replaced with placeholders (which can be turned into actual files again).