Mac OS 10.10
I have an InDesign CS5 document with a spot color background.
When I export to PDF (PDF/X1a) and open the file in Acrobat DC, there is no background color (the separations preview shows there is a spot color in the document, but does not display any ink for this color)
If I open the PDF in Acrobat 9 or X, the background color displays correctly.
Is there a setting in Acrobat DC I don't know about? Do I need to use a different export setting (I've tried several to no avail).
And make sure Acrobat is fully patched -- there have been a number of reports of display anomalies.