If this article does not fix the issue, please follow the steps below to make sure Foxit PDF Editor/Reader can open embedded PDFs in Microsoft Office.
Step 1: Make sure Adobe Acrobat/Reader is uninstalled. Note: Foxit Foxit PDF Editor/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 PDF Editor, the value data of the default string should look exactly as highlighted below:
"C:\Program Files (x86)\Foxit Software\Foxit PDF Editor\FoxitPDFEditor.exe" /Adobe.PDF.Embed
For Foxit Reader, the value data of the default string should look exactly as highlighted below: