In previous versions of Acrobat, I could easily add my signature to a PDF that a colleague had already signed. This was useful (required actually) for documents that needed multiple levels of sign-off. It seems as though this is no longer possible in Acrobat DC unless the original document has signature fields added from the start. Is there any way around this? Most of the forms that I need to sign in this manner are not under my control...changing them is not an option.
Just found a workaround...if I print the PDF to PDF then I can sign the new version. Got the idea from the marketing material that said I'd never have to do that again!
I presume you're using digital signatures. Are you saying that you cannot sign in Acrobat DC exactly the same PDF that you are able to sign in an earlier Acrobat version? This does not seem right.
Is it possible that PDF that you want to sign in DC is a new one which you never tried to sign before in an earlier Acrobat version? If this is the case then your PDF is mostly likely certified with permissions that prevent future signing, or it already contains a previous digital signature which is locked. In either case you cannot sign again in any Acrobat version (at least since Acrobat 7 or 8). When you print your PDF to PDF printer, you effectively remove all existing signatures (although their appearances may still be there), and that allows you to sign. Open the Signature Panel in your original PDF that you want to sign and inspect its existing signatures if it contains any (I think it does).