Signed Document, Changing the Document: Not Allowed

[customer6577]

Hello,

One of my users is using Acrobat Pro 2020 and upon recieving a signed document, she can no longer delete pages, etc. I've reviewed other forum posts on this topic and many of the suggestions are to just save a copy of the PDF if any edits are needed.

The unusual aspect of this, is she's never had this issue with any other signed documents until today. My question is three-fold:

When does the "Not Allowed" setting get applied? Upon signature? Something else?

Is it possible to change the "Not Allowed" setting without making a copy of the PDF?

If the "Not Allowed" setting is expected after the document is signed, why might this issue not have cropped up before now?

Thank you for your consideration

[try67]

A digital signature locks the file from further changes (except for very specific things like filling in form fields, signing it again, or adding comments). This is by design and can't be overcome, to ensure that the signed document is not modified. If you were able to do it in the past then the file wasn't digitally signed, but had a different kind of signature, probably a comment or an image of a "wet" signature.

[Dave Creamer of IDEAS]

I believe it also could have been certified and not locked with a digital signature.

Just to clarify for the OP, a signature CAN lock form fields depending on the form creator's settings.

[MikelKlink]

I believe it also could have been certified and not locked with a digital signature.

"Certification" _is_ a special digital signature, and any digital signature in Acrobat disallows changing the static page content, in particular the deletion of a page. 

[Dave Creamer of IDEAS]

I mis-typed my response. I meant to refer to the locked PDF, not the one that could be edited.