Comments that refuse to delete.

[defaultuzd1s5jbpex9]

So one of my longest running problems has been a comment box that ignore my prompts to delete them when I dont have a use for them. as soon as I hit "delete", it is instantly returned. How do I delete these vexxing little boxes for good?

[Karl Heinz Kremer]

Does this happen with all documents, or just with one, or with a group of documents from the same source? Can you share one of the documents that shows this problem? 

[defaultuzd1s5jbpex9]

This can happen with all documents, its just a luck of the draw in regard to which comments choose to behave normally or not. attached is a blank page with every other comment and item deleted, save for the little comment box in the middle that refuses to die. This particular page is pulled from a template document that I use all the time for work (had to delete classified stuff lol), so this box is nearly always present in some capacity. I want it gone though, out of principle at this point.

[Karl Heinz Kremer]

I can see that this one annotation just does not want to disappear. This is really odd. I tried a few things to cleanup the document, but nothing so far helped. When I copy the comment and paste it, the copy can be deleted, either in the current document, or a new document. 

When I run the preflight profile "Report PDF Syntax Issues", it does find a problem with a "VP" key (VP stands for view port). To figure out what's wrong would requrie a deep dive into the "guts" of the PDF, and unfortunately, I don't have the time for this right now.

To get the attention of Adobe's engineers, you may want to file a bug report: http://www.adobe.com/products/wishform.html - make the sample file you've created available to them. You may not get a response (in my experience, reporting bugs is very much unidrectional communication, and you rarely hear back), but hopefully they will be able to figure out what's going on. You may also want  to get in touch with AutoDesk and report this problem to them (assuming that the PDF file was created in AutoCAD).