.H1S File Extension
File TypeWindows Assistance Platform Help File
What is an H1S file?
Compiled help document format introduced with Windows Vista and also supported in Windows 7; run by the Assistance Platform client (HelpPane.exe), which is installed by default in Windows; used by Microsoft and OEMs for producing help documents, but not used by third-party software developers.
Several pre-installed H1S files can be found in the following directory:
NOTE: H1S files can be compiled using the Apcompnt.exe program included with the Assistance Platform Help Compiler. They can also be decompiled using xHelpMarkup.