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Other HTML Help Problems

Tip: For Windows 64 OS, microsoft ship both a 32 bit and 64 bit version of HTML Help runtime. So when modifying registry settings
remember to change both (a 32 bit app may spawn the 32 bit version while opening a .chm from explorer may open the 64 version).
The 32 bit registry area is under HKEY_CURRENT_USER\Software\Wow6432Node\

HH Security Updates

In a connected world security updates are now a fact of life. Microsoft security updates started with XP SP2 (Aug 2004). Since then a string of updates have blocked some features of HTML Help.
Here are the main HH security updates. The KB articles below contain work-a-rounds to get around the security restrictions. Use with caution.
  1. CHMs no longer work on servers or the web. 
    See KB896054KB896358MS05-026 
  2. ActiveX part of HHCTL.OCX disabled on the web. So TOC/Index controls, Shortcuts etc wont work on server or web.
    See MS05-001KB892675Other Helpware notes
  3. CHMs with a non-CHM file extension no longer open.
    See KB840315KB873343Other Helpware notes
  4. HH Shortcuts restricted on the local PC. This policy was never enabled/enforced by MS. However a network administrator can enable this policy.
    KB810687MS02-055Other Helpware notes
  5. HTML Help Shortcuts wont work on a server. (similar to #2).
    KB323180MS02-055Other Helpware notes
  6. Downloaded CHMs cannot be opened.
    See KB902225MS05-026
  7. HH TOC and Index controls in a frame open topics in the wrong frame.
    See KB896905MS05-026

    Why does my CHM Open Blank?

    The right hand pane of the help viewer shows the IE message "Item canceled" or "Page cannot be displayed".
    1. CHMs must now run from your local PC. See KB896054 for work-a-round.
    2. If you downloaded the CHM from a server do the following.. 
      KB902225 says right-click the file that you want to open, click Properties, and then click Unblock.
    3. Try emptying your Temporary Files Cache (Control Panel > Internet Options > General page > Delete Files...).

    Note: Microsoft should display a clear message telling the confused user why content is not showing in the help file.

    Content (Style Sheet / images) not rendered correctly in help viewer

    Try emptying your Temporary Files Cache (Control Panel > Internet Options > General page > Delete Files...). When the cache fills up IE cannot render its content correctly.

    Note: Microsoft should fix this bug. Is IE7 ok?

    Script Error when clicking Shortcut Link

    Shortcuts can be disabled on the local PC by setting the following policy. See KB810687KB323180

    Registry Key: HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\System\
    Key Name: HelpQualifiedRootDir (String Value) =

    To enable shortcuts simply deleted the registry key name "HelpQualifiedRootDir". Even HelpQualifiedRootDir=<empty string> will enable the policy.  If the problem persists and the registry key name reappears then check with your network administrator as they are probably enforcing the policy.

    Note: Microsoft should display a clear message "shortcuts disabled via policy. See your network administrator". Displaying an unrelated script error is clearly misleading and wastes everyone's time.

    Corruption Help System - Help Won't Open

    Certain Help related DLLs can become unregistered. Usually due to a faulty installer or a 3rd party help authoring tool vendors trying to cut corners. Some vendors (usually Chinese based) actually install and register individual Microsoft help DLLs (they should use hhupd.exe and HtmlHelp.exe). These DLLs are often installed to the wrong location and eventually DLL mismatch problems occurs.

    Download and run MJsDiags (above). This will check and repair DLL problems.

    See also: HH FAQ