We are trying to filter PDF's that are not according to PDF/A Standard, before we upload the files in our archive.
This work is done up to now manually by opening each single file.
Is there a way to find this flag for PDF/A without opening the file itself?
Is the information stored as an attribute so that we can display it in windows explorer?
Like Stefan says "there is no quick and easy way", but ...
In case the final goal is to upload "all" the pdf's to your archive, then you could think about using the "Convert to PDF/A"-feature of PDF-XChange PDF-Tools. There you can choose to skip PDF's that already are PDF/A. All the others (not yet PDF/A) will be converted.
More info about the "PDF-Tools" product: https://www.pdf-xchange.com/product/pdf-tools
More info about "Convert to PDF/A": https://help.pdf-xchange.com/pdfxt9/convert-to-pdfa_t.html