On Windows 7 I'm unable to open any local CHM files in a folder called
Local.Ebooks.CHMs. I tried modifying the registry, but nothing helped. How can I open these CHM files successfully?
As noted in my comment above, I was able to replicate the bug. Strangely enough, it is not the periods that are causing the issue. Windows 7 seems to have a problem with the string
For example, if you try to open a CHM file in
As a workaround, you can rename the folder, removing the period
Video demo: youtube.com/watch?v=7x40fHXRQqU
If the .chm files were downloaded from the internet, then they will be BLOCKED by Windows. You can unblock them by opening the Properties dialog and checking the Unblock box at the bottom.
Microsoft Security Updates 896358 & 840315 block display of CHM file contents when opened from a network drive (or a UNC path). This is window's attempt to stop attack vectors for viruses/mal-ware from infecting your computer and has blocked out the .chm file that draw data over the "InfoTech" protocol, which this chm file uses.
Microsoft's summary of the problem: http://support.microsoft.com/kb/896054