Whenever you release an updated family of Help files, your setup program should run the following command on the master (default) Help file if you are adding, removing, or updating Help or contents files.
winhlp32 -g
This command forces WinHelp to create a new .gid file for the master contents file, which ensures that users can access the topics in the new or updated Help and contents files. If you do not run this command, users who try to access a topic that has been changed or removed may encounter unexpected results.
How does the GID affect your Help file