Windows XP build 2536

Windows XP build 2536 is an unleaked build of Windows XP. A screenshot of this build was found on a promotional CD located in. According to the KB311201 this build is currently the last known build to support using a beta product key for installation.

The error message occurs because the License control is not initialized properly. This occurs if you are running Windows XP build 2600 (the released version of Windows XP), but you are using a Beta product key (which works only in builds 2536 and earlier). The License agent does not recognize the product key as a valid key.