Have you enabled the rights for your PDF with Adobe Acrobat Pro?
(Enable Additional Features)
That option is greyed out (I suspect because the form was created in LiveCycle). Thank you for your help though.
It is not because it was created in LiveCycle that it is greyed out. You have to enable additional rights for each PDF to be able to save them.
Another possibility which I don't think that could be then reason why, when a PDF is already opened in Adobe Reader or Acrobat Pro, the file is set to Read-Only and cannot be saved or changed.
Ah, I see. I disabled opening as PDF/A, and then I was able to enable additional features, as you said.
I clicked File > Save As > Reader Extended PDF > Enable Additional Features
I then closed the file and opened it again, then set Acrobat preferences to : 'View documents in PDF/A mode: Never.' Acrobat then, once again, recognised my PDF form as a PDF/A document and made it read-only, which I wanted to prevent.
Thank you for your help. Unfortunately, I have already tried the solution provided by that blog, when trying to use pre-flight I get the message: Preflight is unable to perform any fixups on this document as its author did not grant the necessary permissions.' I am the form author, and I do not know what permissions will enable this.
Alright, let's try something new to fix this... I hope it will work.
1) Open your PDF with Acrobat Pro.
2) Press Ctrl + P to access the print options
3) On top of the window there is Printer: Print# (dropdown), properties and advanced
4) Click on the dropdown and choose Adobe PDF
5) Click print on the bottom of the window
6) Save the PDF with another name and re-try to Enable Additional Features
Thanks very much for all your help, but I'm afraid that still did not work. Using the "print as PDF" solution removed the form elements from the document, and still made it PDF/A