I've been filling out IRS PDFs and saving the form data for YEARS. Now, with the 2018 IRS Forms, I'm getting the "You cannot save data typed into this form" error.
I've tried this on both WIn 10 & Win 7, downloading the pdf file through every browser I have (Chrome, FireFox, IE, Edge)
What gives? What am I doing wrong? Did the IRS mess up their forms this year? I can still open the 2017 forms, but the security properties look different on them. The 2018 files say Filling of Form Fields is allowed, but Page Extractions, Commenting, Signing, Creation of Template Pages, and Document Assembly is not allowed.
I have encountered this many, many times with various government forms. The olny thing that works for me is downloading the document and opening it directly inside full scale Acrobat DC.
I just tested it with the form in your link which is a READ ONLY file when viewed from my browser's API. But after downloading and lanching it in Acrobat DC, the fields are indeed fillable and the document can be saved if you rename it.
This time of year, I guess the Acrobat servers are getting a lot of traffic.