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.
- Take the browser out of the equation by making a change in Adobe Reader.
- Open Adobe Reader.
- Select Edit, Preferences, Internet.
- Unmark Display PDF in browser. The PDF files will now open in Adobe Reader, not a browser.
- 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.