I don’t want to upload all my designs to your company servers, but sync dialog in settings doesn’t have such an option (I’m using free version). Am I doing something wrong or this software is supposed to force you to share all your designs?
Are you signed in on multiple devices with the same account? If so, you might have to sign out to stop the syncing.
Are you sure ?
I thought that since an update, the choice was no longer possible. Synchronization is done by default. 
I‘m not sure about anything by default, I‘m just trying to use the little experience I have to help others 