When opening a PDF file in Word 2016, by default if PowerPDF is installed, Word calls the Nuance Convert Assistant to convert the PDF into a Word document. The customer requires that Word converts PDF file itself when opening a PDF, and not launch Nuance Convert Assistant.
Close Word 2016
Run the following command from an Elevated Command Prompt.
regsvr32.exe /u "C:\Program Files (x86)\Common Files\Microsoft Shared\TextConv\NPDFCG.cnv"
When Word is started it won't use the Nuance Convert Assistant anymore.