KF-PDF-ID: The file identifier is missing
This code shows up when an electronic invoice is validated. Here is what it means, why it fires, and what to change in the file.
Why this code appears
The end-of-file dictionary (trailer) carries no /ID, the two strings that identify the document. PDF/A requires it, and a validator such as veraPDF rejects the file. Some libraries, pdf-lib among them, do not write it on their own.
How to fix it
Have /ID [<…> <…>] written when saving: two 16-byte strings, equal for a newly created file. A hash of the content works, and keeps the export reproducible.
Where it happens
This check is ours, not a code from the standard: we do not cover enough of EN 16931 to borrow its numbers, and a misattributed official code would send you to fix the wrong field. It concerns PDF.