Disable the Sync Button for SharePoint Document libraries
With SharePoint 2013, you can use OneDrive for Business(SkyDrive Pro) to sync the documents of a SharePoint document library down to your machine for offline access. Any user that has access to the document library will be able to Sync that library. There are positives and negatives about this. We will cover those later, but for this blog, we will talk about how you can disable the Sync so no user can sync that library down to there machine.
If you log into your SharePoint site, and click on a document library, you should see a Sync button on the top right.
This will take you into some search settings, and the setting for offline availability. You will see a line that says Offline Client Availability, and set the the option to no, then hit OK