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I work with PDF files that typically contain up to 200 pages (created from MS Word). I use highlights, comments, shapes, lines and text boxes in the PDF file to annotate the document. I frequently will have a few hundred comment objects in each pdf document.

The problem is that, almost always, my documents get to the point where I start getting this error message whenever I try to save the annotated pdf. Many times I can just try the save again and it will work the second time.  But, almost always when I keep working with a document and keep adding comment objects, the annotated pdf eventually just won't save anymore.

Is Acrobat DC known to become unstable at a certain file size or after adding a certain number of comment objects?  Or after saving a file a certain number of times?

I've tried optimizing the files, but that doesn't seem to help. 

Are there any utilities that will find and fix corrupted pdf files? 

Yours from a world of pdf pain...