With Sync Pro, when linking devices with one identity, you can choose between 3 different modes to control how much data is moved to each of your devices. Disconnected moves no data at all; Selective Sync moves only file and folder names and allows you to choose individual files to sync; Synced moves all the files. Selected mode shows up in 'Identity' menu in Sync settings.
Disconnected folders allow you to see the folders available from your linked devices without taking up any space on the local device. You can connect them later, and start syncing whenever any peer in the swarm is online.
This is what a disconnected folder will look like:
Note that on the source computer (the one where the folder was initially added) the same folder will appear in the "Synced" state. This is due to the fact that the user who initiates sharing has access to 100% of data in the folder and appears to be the owner from the very beginning.
In this mode, all the files reside on Computer 1 only, whereas the other two devices ‘see’ the folder but don’t have its contents. When you click on the ‘Connect’ button on the folder in Disconnected mode, sync will ask you where to put the file on your local device, and then all of the files will be represented in your file browser by placeholder files.
Mobile: to connect the folder, tap on it and then hit 'OK'
Desktop: hover the mouse over the folder in Disconnected state, then hit ‘Connect'
Selective Sync Mode
Folders in Selective Sync take up minimal space on your hard drive, and allow you to see the full file list in your file browser (or in the Sync mobile app). The ‘real’ files inside the folder are represented by placeholder files in the file system.
Here’s how a Selective Sync folder looks like in the Sync window on another computer:
Double-click a folder in Sync to open it in your file browser (Finder on Mac, or Windows Explorer on Windows) and you’ll see that the placeholder files have the extension .rsls:
With “Selective Sync” on, when you open a Synced folder, you will see transparent placeholder files. Double-click a placeholder to sync and open it (the file will not automatically open if it takes more than one minute to receive it). Else you can right-click on a file (or several selected files) and pick "Sync to this device" menu. Because of Sync's peer-to-peer architecture, you must ensure that at least one peer that has the files is online to sync the file. This file will be automatically updated when a newer version is saved on any connected peer with permission to write to the folder.
When “Selective Sync” is on, previously synced files revert to placeholders when deleted. Placeholder files are very small, so they won’t fill up your hard drive. You can either right-click and use the contextual menu options to delete the file, drag-and-drop to the trash can. Sync will replace it with a small-size placeholder, which you can start syncing again whenever you are ready.
Option "Remove from this device" reverts the local copy to a placeholder, files on other peers remain intact. Before reverting file to a placeholder, make sure that other peers have a copy of file so you can later download it!
Option "Remove from all devices" removes the files from all peers, and puts it to Archive there.
The Selective Sync synchronization state is especially important for devices with limited capacity (mobile phones or desktops with solid state drives). Even if your computer or phone has very little disk space, you don’t need to worry about synced data taking it all up. In the Selective Sync mode, Sync will let you have full access to the contents of the folders, let you see what’s inside without copying the actual data to your device, thus saving precious space. When you make up your mind on the files you would like to get in full, just click on their names - and Sync will copy them to your device.
Synced folders synchronize all of the content of the folder between the devices. All additions, deletions, and changes of the files in the folder will automatically be synced to all connected peers.
To switch to the Synced mode (per folder), go to Folder Preferences > Turn Selective Sync OFF:
To change the mode of a device, go to Preferences -> Identity -> Default connect folder mode: