If you’re rolling out Windows 10 build 1511 or higher, you may have a problem with your offline files. If the network folders are on a Windows 2012 R2 share, you probably liked the sound of the feature continuous availability of the share. If you made your share continuously available, they can no longer be synced offline.
Why? I guess it the features conflict and starting in 1511 it’s blocked. Once you turn CA off on the share (and restart your client) the share will again be available to sync offline.