If this article does not fix the issue, please follow the steps below to make sure PhantomPDF/Reader can open embedded PDFs in Microsoft Office.
Step 1: Make sure Adobe Acrobat/Reader is uninstalled. Note: Foxit PhantomPDF/Reader is only able to open embedded PDFs in Office applications if Adobe Acrobat/Reader is not present.
Step 2: Follow the steps in this article.
Step 3: Open Registry and navigate to:
For Foxit PhantomPDF, the value data of the default string should look exactly as highlighted below:
For Foxit Reader, the value data of the default string should look exactly as highlighted below: