PCK, System Center Configuration Manager (.pck)
The PCK System file format
Files of the PCK format are used by an administration program called System Center Configuration Manager (SCCM). This program helps users to administer a group of Windows computer systems. The PCK file contains a package that stores different application as well as system files. It is used to update the Windows versions of the administrated systems.
Technical details of PCK files
In order to update the computer systems, the PCK file has to be compressed with all files needed for the update first. This is done by the SCCM. Afterward, the bundle can be sent to the distributing computer. All computers within the system can then download the PCK from the distributing system. Before SCCM replaced it, the PCK file was used by a program called System Management Server (SMS).