GURU PDF forms are designed for use with Adobe Acrobat Reader or Adobe Acrobat Pro. Each browser (Chrome, Firefox, Internet Explorer, etc) has a built-in PDF viewer making it the default PDF viewer without asking users. These built-in viewers do not necessarily support all features required for PDF Forms. Similarly, many calculations are not supported by other stand-alone PDF readers (for example, Nuance). If you experience problems downloading or opening documents, right click on the link on the Forms Locator Screen, select 'Save Link As' (or similar language) and save the file. The document can then be opened in either Adobe Acrobat Reader or Adobe Acrobat Pro from the saved location.