Due to the ongoing popularity of Windows XP Professional as a robust and stable operating system, the inventory of product keys has been reduced to the point where it is necessary to add more keys in order to avoid impacting end users of Embedded Systems. These are the product keys that are printed on the Certificates of Authenticity (COAs) affixed to Embedded Systems preinstalled with Windows XP Professional for Embedded Systems.

To address the shortage of product keys, MS has released SP2c which expands the product key range to support distribution of Windows XP Professional for Embedded Systems through end of life which is currently planned for December 31, 2016.