For questions related specifically to the Offline Files feature of Microsoft Windows.
Offline Files is a feature of Microsoft Windows which makes a local copy of files on network shares. When the computer is disconnected from the network, files in the network folders which have been enabled for offline access can still be accessed. When the computer is reconnected, the changed files are synced in the background.
More information
http://windows.microsoft.com/en-ca/windows/understanding-offline-files