HLP Viewer

Windows 10 and 11 no longer open old Windows Help (.hlp) files. HLP Viewer reads them in its own window — contents, index, search, links, popups and pictures — without WinHlp32, administrator rights or replacing system files. Pro converts them to PDF or HTML.

Get it from Microsoft Store

The PuTTY help file open in HLP Viewer: the contents tree on the left and a topic with links on the right. — Contents from the .cnt file, and a topic with working links. Select the image to view it at a larger size.

Open files from the app

Drag a .hlp file into the window, or click Open. Windows protects the .hlp file type, so double-clicking a .hlp file can't open this app — and HLP Viewer doesn't change anything in Windows to get around that. Recent files are one click away.

Free: read the whole help file

WinHelp 3.0, 3.1 and 4.0 (Windows 95) help files.
Contents tree from the .cnt file next to the help file, or a list of all topics when there is none.
Keyword index and full-text search, with the words you searched for highlighted.
Links, popup boxes, back and forward, and links into other .hlp files in the same folder.
Fonts, tables and pictures: bitmaps, hotspot pictures and WMF drawings.
Text encoding is detected automatically (for example Korean or Cyrillic help files); you can also choose it by hand.

An Open Watcom IDE help topic with a large color picture, and the contents tree on the left. — Pictures are shown at their original size.

Pro: keep it as PDF or HTML

Free	Pro ($9.99, one-time)
Open, contents, topic list	Save as PDF, with the contents as bookmarks
Keyword index, full-text search	Save as HTML (one page and a picture folder)
Links, popups, pictures	Convert a whole folder to PDF or HTML, with a list of files that failed
Automatic text encoding	Print the current topic

Pro is a one-time purchase. No subscription. Check the local price in Microsoft Store.

Full-text search for — Full-text search marks every match in the topic.

Tested, and what was not

41 help files were opened and saved as PDF and HTML in the app, and about 225 more WinHelp files were read by the parser — none failed.
102 Korean Windows 3.1 and Windows 95 help files: the text encoding was detected correctly for every one.
Japanese and Chinese help files have not been tested yet. If their text looks garbled, choose the encoding at the bottom of the window.
Help macros (buttons, running programs, secondary windows) are not run; their links and buttons are shown but do nothing.
Not supported: EMF pictures, Multimedia Viewer (.mvb) files, and compiled HTML Help (.chm), which Windows still opens.

Private by design

Help files are read on your PC and never uploaded. The app collects nothing; Microsoft Store handles the Pro purchase. Read the HLP Viewer privacy policy.

Credits

Help files in the screenshots: PuTTY 0.60 help (MIT License) and Open Watcom 1.9 IDE help (Sybase Open Watcom Public License 1.0).