Solution to CHM File Failure

Transferred from neeao's blog

Open a Help file in. chm format to check the information. Double-click the file as usual. The prompt is:
File cannot be opened. CHM
I checked it online and found a solution:

Reference TIPS: CHM stands for Compiled HTML. A file icon with the CHM extension is usually a document icon with a question mark, indicating a help document. It is a file in the help document format provided by Microsoft since Windows 98, used to replace the HLP (HELP) file in Windows 95. Since Windows 98, Microsoft has built-in interpreters (tools for opening the CHM File) in the operating system, that is, HH. EXE under the Windows installation directory. The CHM file can be generated by providing HTML Help Workshop for free on the official website. Its source file is an HTML file. Nowadays, many e-books on the Internet are produced in chm format.

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A few days ago, I wanted to open a CHM-format ebook and check something. I did not expect that I could not open the page when I opened the window. Because it has been seldom used for help, I do not know when this problem began. Because I don't have time to think about it, I first checked the information on the Internet and put the problem down.

The same problem occurred when I opened a CHM document again today. This time has time. After a try, almost all CHM files cannot be opened. It seems that an error occurs in a key step in the open process (that is, the operation process in the system, not the human operation process.

The essence of CHM is to use several special protocols to access and compress webpages in CHM files. So I guess there may be a ghost in the firewall. So I checked all the firewalls carefully and did not limit the reading of CHM files. If you disable all firewalls, CHM still cannot be read normally.

It may be that a component necessary for HH. EXE has a problem. But I don't know what components will be used by HH. EXE, so I checked it online. Someone suggested registering hhctrl. dll again. I found hhctrl. ocx IN THE SYSTEM directory, but not hhctrl. dll. If it is an error on the internet, register hhctrl. ocx again and try regsvr32 hhctrl. ocx. Still cannot read CHM normally.

In this case, it is very likely that there is a problem with the protocol. HH. EXE uses MS-its and other protocols. These protocols should be provided by a DLL file. The problem is, what is the DLL? Then Google searches for the MS-its protocol. Finally, it turns out that it is an itss. dll service. However, the solution found on the Internet is to modify the registry. Looking at the bunch of registry items, you have a headache. Please try the lazy method first-re-register dll: regsvr32 itss. dll.

Try again. Hey, okay, CHM can be opened again.

Most of the reasons why CHM cannot be opened are due to Microsoft's recently fixed HTML Help vulnerability. However, the situation on my machine is not quite consistent with the characteristics. I can read CHM again.