Forum Discussion
Disable sync for external users
This works for Desktops and laptops and surface tablets.
http://www.learningsharepoint.com/2016/03/11/sync-client-operations-block-and-unblock-domains-file-extensions-mac-pcs/
For controlling iPads (since they can’t be domain joined) there is a separate parameter setting for Set-SPOTenantSyncClientRestriction to control Mac devices. If you add -BlockMacSync to your settings that will block all the iPads from syncing.
On Iphones you need to implement Information Rights Management to prevent taking files offline since they aren't technically using Onedrive sync client.
You can also control what computers can sync OneDrive based on the domain
they are joined to in the OneDrive Admin center. If you turn this on and
specify a non-existent domain then users on your domain joined PCs will nto
be able to Sync OneDrive.
I'm not sure how it works in android tablets though.
Hope this helps Let me know.