At the beginning of the property set stream is a header. It consists of a byte-order indicator, a format version, the originating operating system version, the CLSID, and a reserved field.
The following pseudo-structure illustrates the header:
typedef struct tagPROPERTYSETHEADER { // Header WORD wByteOrder ; // Always 0xFFFE WORD wFormat ; // Always 0 DWORD dwOSVer ; // System version CLSID clsID ; // Application CLSID DWORD reserved ; // Should be 1 } PROPERTYSETHEADER;