A CBK file is a backup configuration file created by various programs, such as InterSystems Cache and Devicescape Enterprise-Managed AP. It stores a backup of system files and configuration information.

CBK files typically appear with a file name and the date the backup was created. They often are named with the following convention: [Name of the backup]_[yyyymmdd]_[nnn].cbk with the [yyyymmdd] being the date of creation and the [nnn] being the number of backups created that day. An example of a CBK filename is FullDBList_20101104_002.cbk.