Verify a PDF against PDF/X or PDF/A criteria

PDF/X and PDF/A files can be created in a variety of ways, such as by using Acrobat Distiller. If you open a PDF/X or PDF/A file created by Distiller or another application and start the Preflight tool, you may see the Verify PDF/X icon  or Verify PDF/A icon at the bottom left of the Preflight dialog box. This icon indicates that you need to verify that the file is PDF/X or PDF/A compliant. The PDF/X or PDF/A standard used to create the file and the color settings file associated with the file appear next to the icon.