Backup file created by Citrix virtualization software; saves the configuration for a virtual server host so that it can be restored and restarted if it unexpectedly quits; does not include the virtual machines running on the server. XBK files can be created (and restored) by XenServer or XenClient, a Windows GUI used for managing XenServer hosts.
File created by SMART Notebook software, a program used to create and deliver classroom lessons; may contain images, notes, diagrams, audio, and video; used for storing and distributing classroom notes; can be exported to .HTML or .PDF files in SMART Notebook software. XBK files can be converted to the newer .NOTEBOOK format in more recent versions of SMART Notebook software.