Trying to Understand "Compute Modifications" when none were made

Question

Hello.
I have certified documents that are used as checklists and later signed multiple times by multiple people.  Sometimes we have issues with those signatures and have to get people to resign.  The question here is, all those signatures show that they have made modifications (using the Compute Modifications button) - but there have been no modifications before, or since.....am I misunderstanding what this term means?
Appreciate all help.
Stephanie.

Answer 1

We were running into a somewhat similar issue and I was finally able to solve it.
In our case we were creating a PDF and adding some form fields to it, then we added a background image to the document (The background was a stripped down Illustrator PDF with pretty much every option turned off). The PDF was then uploaded to our server where it was filled via a web service with data when a customer requested it. We had the same issue that Acrobat Pro fired the "Save changes" on close but Acrobat reader was fine. After fighting with it for a while I tried uploading a blank PDF with no background or fields to the web service. The resulting PDF still fired the error - so it was not an issue with the image or fields directly. I then took the PDF (without the image and fields) and selected Advanced > PDF Optimizer (it asked me to re-save the PDF as an optimized version and didn't throw any errors while saving) and uploaded that version to the server. That way worked - no save prompt on close. So I went back to the full blown PDF with the fields and BG image and ran the optimizer. When optimizing Acrobat returned one warning - the BG image had a mask that could not be optimized. I went back to Illustrator and exported as a TIFF, had Acrobat make a PDF from the TIFF and then had Acrobat do a optimized save of that PDF image then re-imported the now optimized PDF BG image into the full blown PDF as a new BG image. I then optimized the full blown again - this time getting no error about the mask (I think it was removed when I optimized the image PDF). I uploaded to the server and the message to save was gone.
The short version of this is try running the Advanced > PDF optimizer on your document prior to uploading it for data insert - I think it strips out all the "fluff" that pro keeps with the document essentially making it a "Acrobat Reader" version and without all the fluff the Would you like to save changes issue is gone.