At present a PDF Form created in LifeCycle are no longer able to be edited in latest versions of Adobe Acrobat Professional (not Reader) unless the Form was created in an older version of LifeCycle released with Adobe Acrobat 8.0 (and possibly 8.1)
In these versions of LifeCycle Adobe created and saved both a "new" style form and the "old" style form data in the same package.
If this is the case then you can use the situation described above to open the form in (old) version of LifeCycle, save it as a "static PDF Form" (rather than dynamic) and use the public domain pdf tool to strip the "XFA" header.
Then when you open the form in Adobe Acrobate (not reader) it will not complain about needing to open it in LifeCycle but also allow you to edit it and have access to scripts etc.
3You can also use the "Extract Pages" function in "Organize Pages" mode in Acrobat by selecting all of the pages and right-clicking. This gives you PDF's that are editable in Acrobat. – BlueSam – 2016-01-30T20:11:22.510
@BlueSam, that doesn't work on secured documents, which is when the issue described in this entry occurs to begin with. So, your proposed solution is incorrect. – PKHunter – 2017-09-15T21:16:12.770
Actually BlueSam's comment was EXACTLY what I needed. I have multiple forms that are unsecured, but were created with LiveCycle, preventing me from attaching additional pages (the only thing I needed to do!). pdftk didn't help, but "Extract Pages" gave me the file I needed without removing form fields. In my case document was unrestricted except that it was created in LiveCycle, preventing me from editing it as a standard PDF. – dr.nixon – 2017-10-25T14:24:37.883