viewing an HTML help file over a network

[Tech_Writer_KC]

Today I ran into something interesting, and was wondering if anyone knew what the cause might be.

Basically, what are the requirements for viewing a .chm file over a network? Previously, opening a .chm from a network location would cause it to display a "file now found" message on my system, but today I unintentionally opened one and found it worked perfectly. I've just changed computers here at work, which included moving from an XP to a Vista machine, and thought that the change in OS might have something to do with it.

However, a coworker who's in the process of changing his computers (and has both running at the moment) tested this for me, and found that he could open his from his old XP machine, but not from his new Vista machine, so it doesn't look like this is an XP vs Vista issue.

We were wondering if viewing a .chm over a network is tied to any rights or permissions settings, and I thought I'd ask here in case someone already knows.

Thanks in advance!

[Peter Grainge]

You should only be able to run a CHM over a network if one the of the registry changes described on my site has been made.

http://www.grainge.org/pages/authoring/chm_mspatch/896358.htm

[kfielder]

For some reason your links aren't working.

[Pete_Lees]

Hi,

Just to add that I believe you're right as far as the XP vs. Vista issue is concerned. There shouldn't be any difference between these two operating systems in the way they handle remotely accessed help files.

If we assume that the same registry changes have been made to all four of your machines, there are at least two reasons why the contents of remote help files may be viewable from one machine but not from another.

• 
  
• If IE7 is installed, and you have set the MaxAllowedZone registry key to 1 so that you can view the contents of all help files in the Local Intranet zone, you must also make an additional change to the Internet options in IE before you can access the help files. See this article for more information:
  
  http://weblog.helpware.net/?p=50
  
  This additional change was unnecessary in IE6 and earlier. Perhaps the version of IE is a factor in your case?
  
  
• The UrlAllowList registry key, which is designed to let you view the help files in specific network folders only, was reportedly broken for quite a long period. This was eventually fixed by a Microsoft update last year, but machines that haven't been updated for some time may still exhibit the problem. See:
  
  http://helpware.net/FAR/far_faq.htm#kb_OpenCHMs
  

Pete

[RoboColum_n_]

They work for me. Try again.

[Tech_Writer_KC]

As an update:

A co-worker of mine discovered a file named "HTMLHelp.reg" that is on some of our systems, but not all.

If you have this file, it seems that you can view .chm files over a network. If you don't, you can't. Unfortunately he is out at the moment and I can't find where this file is supposed to be in Vista.

He found it in an XP machine and copied it to Vista, where it appears to work. What's odd is that several of our new Vista machines allow us to view .chm files over a network right "out of the box", without any changes or updates made to the registry or elsewhere, or AFAIK without this file being specifically added or altered.

Anyone familiar with where to find this file in Vista? We are now trying to see if we can view chm files from SharePoint (even machines with the above file cannot view chm files opened directly from SharePoint).

[Pete_Lees]

Hi, again,

> What's odd is that several of our new Vista machines allow us to view .chm
> files over a network right "out of the box", without any changes or
> updates made to the registry or elsewhere, or AFAIK without this file
> being specifically added or altered.

That's certainly odd. If you open Registry Editor and navigate to the following key, is there nothing there that might permit you to view remotely-accessed .chm files?

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\HTMLHelp\1.x\ItssRestrictions

I'd expect to find a UrlAllowList or MaxAllowedZone value that unblocks the remote .chm files in specified nework folders or security zones. In the absence of these values, viewing remote files should be impossible.

> Anyone familiar with where to find this file in Vista?

It wouldn't be shipped with Vista, as by making the registry changes you're relaxing the security of your PC and potentially exposing it to attacks from malware writers — not something that Microsoft could ever be seen to encourage.

> even machines with the above file cannot view chm files opened directly
> from SharePoint

Yes, that's right. The same security update is responsible for both issues, but each issue has its own set of workarounds.

Pete