For each PDF/A-1 validation issue we try to explain what it means and, if possible how to resolve it. For a more technical explanation of the issue we quote the related section of the ISO 19005-1 PDF/A Specification.
This is commonly caused by files without 8-bit binary markers in the header. Many so-called PDF/A creation products fail to place these markers in the header and thus produce non-compliant files. Without these markers, the PDF files could be damaged when processed or when transported over the internet.
How can I fix it?
Use Solid PDF Tools to adjust the PDF File structure. It will adjust and correct Header, Trailer and binary markers to create a PDF/A compliant file.
6.1.2 - ISO 19005-1 PDF/A Specification:
The % character of the file header shall occur at byte offset 0 of the file.
The file header line shall be immediately followed by a comment consisting of a % character followed by at least four characters, each of whose encoded byte values shall have a decimal value greater than 127.
NOTE: The presence of encoded character byte values greater than decimal 127 near the beginning of a file is used by various software tools and protocols to classify the file as containing 8-bit binary data that should be preserved during processing.