Unblocking CHMs

Windows security may block CHM files downloaded from the internet. When opening a CHM file, the file may open but display one of the following messages instead of the expected content:

  • Navigation to the webpage was canceled.
  • Action canceled.

If either of these messages display, unblock the file.

  1. In Windows Explorer, right-click the SDK_Documentation.chm file and choose Properties.
  2. On the General tab, click the button labeled Unblock.
  3. Click OK.
  4. Open the file.

For more information, refer to the Microsoft knowledge base article: