Error when running Pre-flight

[thigbieHHR]

When I run Preflight on a PDF to check for PDFa compliance I receive the following error:

I'm far from an Adobe expert so any help with this error would be much appreciated

[Thom Parker · Accepted solution]

There is an error or unrecognized feature somewhere in the content of your PDF. I would suggest getting Acrobat to rewrite the PDF. There are several options for this from performing a "SaveAs" to Saving as Optimized. There are even Preflight "Fixups" that may do the job.

[thigbieHHR]

Thanks Thom.

I called support and the problem with this particular PDF was that it was created with a third-party PDF maker, which Preflight didn't work well with.  Printing to a new PDF with the Adobe Printer, saving as PDF\a, and then running Preflight did the trick.

Thanks very much