EMF files damaged during PDF export in Microsoft Word

I believe I have found a solution:

1. Open the EMF file in Microsoft PowerPoint.
2. Right click the image, and select "Save as image...".
3. Save the image as a Windows Metafile (*.wmf) -- not an Enhanced Windows Metafile (*.emf).
4. The obtained file can be used without problems in Word -- it will not cause any problems when the document is exported to a PDF file.

Do NOT use the built-in PDF export feature of Word, it will break your EMF figures.

I found a solution.

1. Open your word file.
2. file -> print.
3. select the printer as "Microsoft Print to PDF".
4. click the print button.
5. save the PDF file.

This works for Word 2016.