PAC 2 Error
PDF/UA identifier missing
PDF/UA > Metadata and Settings > Metadata > PDF/UA identifier
Matterhorn Protocol Checkpoint 06-002: The metadata stream in the Catalog dictionary does not include the PDF/UA identifier.
The PDF/UA ID attests that the PDF is ISO 14289 (PDF/UA) compliant. It should be added as the final remediation step; otherwise you would kind of be fibbing.
To add the PDF/UA ID using Acrobat Pro X or XI you will need the required snippet of metadata in an XMP file. If you have knowledge and experience with XML/XMP you can create the file, otherwise feel free to download this one and save it with an xmp (not txt) extension. This XMP file was created by a kind and knowledgeable participant in the Adobe Acrobat forum, by repairing an imperfect one that I had created. In my experience it has always worked, even for files that are both PDF/UA and PDF/A (my imperfect attempt proved to be incompatible with /A).
In Acrobat Pro, File > Properties > on the Description tab of the Document Properties dialog, click the Additional Metadata button > Click “Advanced” (near the top left of the dialog) > Click the Append button > In the Append dialog, select the XMP file and click the Open button
Alternative Suggestion, only if using Acrobat Pro DC
Tools > Print Production > Preflight
In the Preflight dialog, on the Profiles tab, click the Single Fixup wrench icon (the rightmost of the three icons next to the “Show all” button). Expand “Document info and Metadata” and select “Set PDF/UA-1 entry”. Click the “Fix” button. When prompted, save to a new file name.
Video version of this suggestion:
Video version of the alternative suggestion using Acrobat Pro DC: