If you are unable to view help files downloaded from the Keysight website.


In September 2005, Microsoft released a security patch for Windows operating systems that protects PCs from the threat of malicious code that could reside in compiled HTML help files (*.chm files). When a *.chm file is downloaded to a PC that has the patch installed, the file opens with one of the following error messages displayed:

  • Action canceled
  • The page cannot be displayed

Workaround: After downloading the file to your PC, open it from the location it was saved and a security warning appears. To view the help system, clear the checkmark from the "Always ask before opening this file" check box. The help system can now be viewed from the PC. Alternatively, right-click the file you want to open, click Properties and then click Unblock.

Note: No workaround exists for viewing *.chm files remotely. You must first download the file to your PC and then use the workaround described above.

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