I cannot seem to open XFA-type PDFs. When using read OCR, read text, document understanding, or other read documents on the PDF, I receive the following error regarding the PDF. This typically happens when the PDF program does not support XFA-type PDFS. See the message box on the right for the error.
I went ahead and did some research on this issue.
The root cause here is that the library used by the Document Understanding package to do this task does not support XFA forms. The functionality is actually deprecated and not part of the PDF 2.0 standard).
As a workaround, you could try identifying the files that use XFA forms and “print” or otherwise try to transform them into flat PDF files that could then be processed with OCR.