Opening CHM Files in Vista

If any of you have been following me on Twitter recently, you know I've been researching the installation of TFS. I had pretty good luck with a lot of websites regarding TFS 2008, but not so much with 2010 Beta 1 (naturally). The only source for detailed documentation was Microsoft, so I went with what I had and downloaded the document. If you hadn't guessed yet from the title of this post, the file was a .chm extension.

After downloading the .chm file, I proceeded to open it. Much to my dismay, it opened but the pages would not load. I was getting 404 errors on every topic. After spending a few hours searching, I found a solution. Apparently the .chm extension is not secure and Vista removed the ability to read files like that unless they are in a specified 'safe' location. I don't particularly want to have to download any .chm file to an obscure location and then have to find that location again to open the file. Naturally, I searched for a simpler solution.

The solution I found, simpler or no, worked. You guessed it...it's a registry hack.

I have a theory that one can literally do anything with registry hacks...things like make pigs fly or make hell freeze over.

Here's what to do:

1.) Right click your .chm file and select Properties

2.) Click Unblock and select Apply

3.) Open up Regedit (Windows Key + R and type regedit)

4.) Navigate to HKEY_LOCAL_MACHINE\Software\Microsoft\HTMLHelp\1.x\ItssRestrictions

5.) Modify the DWORD MaxAllowedZone to equal 1 (if it doesn't exist, create it)

6.) Close all Internet Explorer Windows and start up your .chm file

That's all there is to it. I haven't had any problems with any .chm files since.

The next post I have coming up (already have most of it written) is on the installation of TFS. Brace yourselves...

Aaron