title: How to fix fillable Pdf form no longer fillable after filling?
body: <p>We created a fillable pdf and distribute to customers for completion. Sometimes we need to correct the customer entered data values in the form fields using the free Adobe Reader.  This has worked well for over a year and this week we received 2 completed forms we can no longer edit.  Security details show filling of form fields is allowed but Adobe Reader can't modify.</p>
  <p>The distributed pdf was created using a paid version of Acrobat.  Document properties of that pdf show the PDF Producer is Adobe PDF library 15, version 1.6 (Acrobat 7.x).  Both the problem pdf's changed the PDF Producer to PDFium, version 1.7 (Acrobat 8.x)</p>
  <p>The free Adobe reader is up-to-date, version 2021.005.20060.</p>
  <p>Update:  I used UglyToad's PdfPig and see all the AcroField Text Boxes no longer exist in the pdf, but the checkboxes are still present.  Issue now is why is PDFium removing the textboxes, and I'm going to guess it changes them to image.</p>