The Windows Help program is not supported in Windows 10, Windows Server 2012 or later versions of Windows Server. The Windows Help program is available for Windows Vista, 7, 8 and 8.1 only.
Microsoft strongly recommends that software developers discontinue using the Windows Help application. Software developers who ship programs that rely on .hlp files are encouraged to transition their Help experience to an alternative Help file format, such as CHM, HTML, or XML. For more information see the MSDN article https://msdn.microsoft.com/en-us/library/windows/desktop/ms728460(v=vs.85).aspx
. While Microsoft develops future Help technologies, we encourage Help authors to continue using HTML Help 1.4. HTML Help 1.4 is included in Windows versions starting with Windows 7.