On the Cubby desktop application, hold your mouse pointer over a cubby's icon to see the sync status indicator.
This is what you might see after you accept an invitation to a shared cubby and then start syncing to your computer called Work.
Note: In the screenshot above, the cloud switch is light gray (inactive) because a share recipient can't turn off the cloud. A cubby's owner is the only one who can toggle the cloud.
When syncing, I see tmp files in my cubby! What's that all about?
The creation of temporary files is part of how Cubby works. While a sync is in progress Cubby creates a temp file (much like browsers do), and the file gets renamed when the transfer is finished.