Depending on the way a PDF file was created, some PDF files can have layers for different elements in the file. This can cause some parts of a PDF file to not display correctly in some apps. To make sure that all parts of a PDF file are visible and display correctly you can flatten all the layers in the PDF file. The steps below are done using Adobe Acrobat Pro DC on a Mac, similar steps should be available on a Windows machine.
- Open the PDF file using Adobe Acrobat Pro DC.
- Choose File > Export a PDF > PostScript.
- In the Save dialog, leave the Format set to PostScript.
- Also in the Save dialog, under Settings, leave the Printer Description File set to Device Independent.
- Click on Save which will save the file with a .ps suffix for PostScript.
- Launch Adobe Acrobat Pro DC and choose File > Open…
- In the Open dialog, change the Show setting to All Files.
- Open the .ps file you saved previously.
- Save the new flattened PDF to a location.