This issue is due to compatibility issues between various versions of Adobe reader and the browsers – Internet Explorer having the most trouble, but Chrome is also affected.

Alternative solutions:

  1. Take the browser out of the equation by making a change in Adobe Reader.
    1. Open Adobe Reader.
    2. Select Edit, Preferences, Internet.
    3. Unmark Display PDF in browser. The PDF files will now open in Adobe Reader, not a browser.
  2. Right click on the User Guide link and choose 'save file as'. This will save locally to the machine and the user can open the guide locally.