PDF/UA identifier is missing or wrong

Messages you may see

• PDF/UA-1 (ISO 14289-1) rule 5-1: The document metadata stream doesn't contain PDF/UA Identification Schema
• PDF/UA-1 (ISO 14289-1) rule 5-2: The "part" property of the PDF/UA Identification Schema is … instead of 1 for PDF/UA-1 conforming file
• PDF/UA-1 (ISO 14289-1) rule 5-3: Property "part" of the PDF/UA Identification Schema has invalid namespace prefix …
• PDF/UA-2 (ISO 14289-2) rule 5-2: The "part" property of the PDF/UA Identification Schema is … instead of 2 for PDF/UA-2 conforming file
• PDF/UA-2 (ISO 14289-2) rule 5-5: The value of "pdfuaid:rev" (…) is not "2024"

What the rule requires

Clause 5 of ISO 14289-1 (PDF/UA-1) defines how a file identifies itself: through the PDF/UA identification schema in the XMP metadata stream of the document catalog. The Matterhorn Protocol 1.1 lists the identifier under checkpoint 06 (Metadata).

Our checker tests the file against the part you select; with the automatic choice it uses PDF/UA-2 if the file declares part 2, and PDF/UA-1 otherwise. A PDF/UA-1 file checked against PDF/UA-2 therefore fails rule 5-2, and the other way round. The metadata stream itself is required by clause 7.1 (UA-1) and 8.11.1 (UA-2); a missing title in it is covered by the document title rules.

Why it matters

The identifier does not change what a screen reader reads. It tells software and people which standard the author claims to meet, so that validators apply the right rules and organisations can sort and track their documents.

The identifier is only a claim. A file with pdfuaid:part 1 can still have missing alternative text or a wrong reading order. Conversely, a well-made PDF without the identifier cannot claim PDF/UA. This is why the identifier should be the last step, never a shortcut.

Common causes

• The authoring program has no setting for it. Word's PDF options offer none, and InDesign's Standard menu covers only PDF/X.
• The PDF was tagged and corrected in Acrobat, but the identifier was never added.
• An optimiser or a "sanitise" function removed the XMP metadata.
• The file carries the identifier for the other part (for example part 2 while being checked against PDF/UA-1).
• A script or tool wrote the property with a different prefix, such as ua:part.

Example

XMP metadata with a title but without the identifier fails rule 5-1. The corrected PDF/UA-1 version adds the namespace and pdfuaid:part:

<x:xmpmeta xmlns:x="adobe:ns:meta/">
  <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
    <rdf:Description rdf:about=""
        xmlns:dc="http://purl.org/dc/elements/1.1/"
        xmlns:pdfuaid="http://www.aiim.org/pdfua/ns/id/">
      <dc:title>
        <rdf:Alt><rdf:li xml:lang="x-default">Annual report 2025</rdf:li></rdf:Alt>
      </dc:title>
      <pdfuaid:part>1</pdfuaid:part>
    </rdf:Description>
  </rdf:RDF>
</x:xmpmeta>

<pdfuaid:part>2</pdfuaid:part>
<pdfuaid:rev>2024</pdfuaid:rev>

1 0 obj
<< /Type /Catalog /Pages 2 0 R /StructTreeRoot 3 0 R
   /MarkInfo << /Marked true >> /Lang (en-GB)
   /Metadata 15 0 R >>
endobj

15 0 obj
<< /Type /Metadata /Subtype /XML /Length 612 >>
stream
… XMP as above …
endstream
endobj

How to fix it

Microsoft Word

Word's PDF options (File > Save a Copy or Save As, file type PDF, More Options > Options) contain no setting for the PDF/UA identifier. Whether a given Word version writes it can be seen in the result of this check.

1. Export with Document structure tags for accessibility selected.
2. Check the PDF and fix all other findings, in Word if possible.
3. Have a person review reading order, alternative texts and tables.
4. Add the identifier in Acrobat Pro as described below.

Adobe InDesign

InDesign's PDF export offers no PDF/UA option: according to Adobe, the Standard menu specifies a PDF/X format. Its compatibility settings end at PDF 1.7, so InDesign cannot produce PDF/UA-2.

1. Export with Create Tagged PDF switched on.
2. Check the PDF and fix the other findings.
3. Add the identifier in Acrobat Pro as described below.

Adobe Acrobat Pro

Acrobat Pro can add the PDF/UA-1 identifier with a Preflight fixup. Deque University describes these steps:

1. Open Preflight (Tools > Print Production > Preflight).
2. Set the library to Acrobat Pro DC 2015 Profiles or PDF Standards.
3. On the Profiles tab, open the single fixups (wrench icon).
4. Expand Document Info and Metadata, select Set PDF/UA-1 entry and choose Fix.
5. Save the file under a new name and check it again.

Questions

Does the identifier make my PDF accessible?

No. It states which standard the file claims to meet. Only the content and structure make it usable, and part of that can only be judged by a person.

Should I add the identifier as soon as the machine check passes?

Only after a manual review as well. Machine checks cover a part of PDF/UA; reading order, alternative text and meaningful tags have to be checked by a person.

Can a file carry part 1 and part 2 at the same time?

No. pdfuaid:part has one value. A PDF 1.7 file can only meet PDF/UA-1; PDF/UA-2 requires PDF 2.0.

Sources

1. ISO 14289-1:2014 – Document management applications – Electronic document file format enhancement for accessibility – Part 1: Use of ISO 32000-1 (PDF/UA-1) – International Organization for Standardization (ISO). Checked on 7 November 2026.
2. ISO 14289-2:2024 – Document management applications – Electronic document file format enhancement for accessibility – Part 2: Use of ISO 32000-2 (PDF/UA-2) – International Organization for Standardization (ISO), 13 March 2024. Checked on 7 November 2026.
3. The Matterhorn Protocol 1.1 – PDF Association. Checked on 7 November 2026.
4. XMP metadata stream in the Catalog dictionary must include the PDF/UA identifier (axe PDF rule) – Deque University. Checked on 8 November 2026.
5. Save or convert to PDF or XPS in Office Desktop apps – Microsoft Support. Checked on 8 November 2026.
6. Adobe PDF export options in InDesign – Adobe (helpx.adobe.com), 2 June 2026. Checked on 7 November 2026.