This form cannot be edited in Adobe Acrobat DC. Please use Adobe LiveCycle Designer to edit this form.

Here’s a solution in case someone runs into this problem again.  It requires you have Adobe Acrobat DC and Microsoft Word.  The trick is to make a copy of the PDF file, sign the copy, export the copy to Word, and finally save the Word document as a new PDF file.  NOTE: The end result is a PDF with no restrictions on editing and all custom formatting removed.  Restrictions and custom fields would have to be added again if needed.)

The problem:

Using Adobe Acrobat DC, you are unable to edit some fields in a PDF file (e.g. i-9.pdf) due to restrictions on the document.  These restrictions are dictated by the signer or certifier of the document. 

Specifically, you cannot:

• edit a field that should be fillable (e.g. the date next to your signature)
• save the file after making changes to fillable fields
• export the file as a Word document

Any attempt to edit the file using the Edit PDF option causes the following message to be displayed:

"This XFA form cannot be edited using Adobe Acrobat."

Saving a copy of the file does not resolve the problem.  If you attempt to remove or change security settings on the file, or export the file as a Microsoft Word document, the following messages are displayed:

"You cannot change security on this document because the document is signed or certified."

"The document has insufficient permission for this operation."

The current restriction on changing the document can be viewed in the file properties as shown below:

The solution:

The only solution is to remove all restrictions on the file.  This can be done in three steps:

1. Creating a copy of the file signed by you.  This removes the restriction for changing the document.
2. Save or export the copied file as a Microsoft Word document.  This removes all remaining restrictions on the document.
3. Lastly, save the Word document as a new PDF file. This creates a PDF file with all restrictions removed, allowing you to make needed changes to the document.

Details:

Use the Fill & Sign option to create a copy of the file certified by you.  This will remove restrictions for changing the document.

Select the Fill & Sign option > Select Sign yourself and add your signature to the file > Select Save > The following message will be displayed:

"This document restricts some Adobe Acrobat features to allow for extended features in Adobe Acrobat Reader.  To create a copy of the document that is not restricted (and has no extended features in Adobe Acrobat Reader), click Save a Copy."

Select "Save a Copy" and assign a new filename (e.g. myfile_signed.pdf)

Open the new (signed) file you just created (note that Acrobat does not automatically open the new file for you).

File > Open > Select myfile_signed.pdf > Open > The new file will open (with restrictions on changing the document removed)

Optional: View the file restrictions to confirm changing the document is now allowed.

Export the signed PDF file to Microsoft Word

File > Export To > Microsoft Word > Word Document > Save the document as a Word document (e.g. myfile_word.docx)

The file should automatically open in Word.

From Microsoft Word, save the Word document as a new PDF file. 

File > Open > Select myfile_word.docx > Open

File > Save As > assign a new name (e.g. myfile_new.pdf) > Select PDF as the file type > click Save

A new PDF file (myfile_new.pdf) will now be available with all restrictions removed.

LiveCycle Designer is what you need. It is not an add on to Acrobat. The whole LiveCycle suite is enterprise server software costing 5 or more figures.