A hotfix is available for systems broken by the MS15-010 (security update for Windows kernel mode driver: February 10, 2015) update.
When trying to restore files or folders on a client that is connected to the Windows Server 2012 or 2012R2 Essentials server from the dashboard, the following error occurs.
A hotfix for this is now available here – https://support.microsoft.com/en-us/kb/3045682
You can read up more information on this issue here – http://blogs.technet.com/b/sbs/archive/2015/03/13/the-ms15-10-security-update-for-windows-server-2012-r2-essentials-and-the-client-restore-functionality.aspx
For windows 7 clients and Server 2012 R2 Essentials, pick Windows 7 and Server 2008 R2, x64 or x86 depending on OS installed. It works!