CHM refuses to open from some folders

Hopefully you have a Windows OS on which you can open .chm files correctly.

Let's say you have a file called A.chm that opens correctly

• Now create a folder called f.column
• Copy A.chm to f.column folder

Now double-click to open the A.chm file in Explorer and you will see a dialog with the message:

Cannot open the file: D:\f.column\API_GB.chm.

Does anybody have any idea why this happens?

This is a developer-related problem, because typically the user will be launching help from an application's help menu, and are likely to believe that the bug is in the application and contact the developer. This is particularly likely to happen in applications that install into the user's profile, because the bug will be triggered if the username happens to contain .col.

Solution 1:

This is a known problem, and it cannot be fixed.

When Microsoft delivered its MSDN Library in the old HTML Help 1.x format, they used .col files to list all the .chm files that were to be included in the collection.

The only solution is to move the CHM to another folder.

Any chm file that is in a folder named *.col* will not open. Example paths that will cause this error:

C:\asdf.col\TFSInstall.chm

C:\Documents and Settings\john.coltrane\Desktop\TFSInstall.chm