Thanks for replying!
Since my initial post I managed to better understand the problem: Windows Help actually works,
until I use the "Heroes of Might and Magic III"
map editor (not the game, the editor).
This map editor ("h3maped.exe") is a standard Windows program from 1999, and uses Windows Help to display useful information: When you right click an object in the editor, a small window pops up with extra info on it, and this uses the old WinXP help system (I know this because Microsoft changed the Help system around Windows 8, and thus broke that map editor).
In Wine, when I call "Help" in this editor, I get the little "Failed to launch Help" error message, and after that, all help, on all (old) Windows programs, is broken until I restart Wine. Something about how that editor (mis)uses the Help system to display popup information seems to crash Wine's "winhlp32.exe".
Not being a developer, I'd be hard-pressed to say what format the HoMM3 map editor's help files are, or what exactly they do to crash the Help system. All I know is that the editor's help seems to be a file called "H3MAPED.HLP" (331.4 kB)...
Now as I said, I have access to a WinXP VM, and could potentially copy the original XP "winhlp32.exe" files and replace Wine's, in a hope they are more resilient, or have the feature the editor tries to use. Do you think it might help, or will it just create a worse mess?
![Shocked :shock:](./images/smilies/icon_eek.gif)