You can open companion files in external applications thanks to the following VBA code snippet. For instance, this will open the PDF file named UserGuide.pdf.

 

Sub OpenUserGuide()

 

   FileCopy PathToCompiledFile("UserGuide.pdf"), Environ("temp") & "/UserGuide.pdf")

   ActiveWorkbook.FollowHyperlink Environ("temp") & "/UserGuide.pdf"

 

End Sub