During adding comments PDF got corrupt.

Question

We have given the PDF to our client created using Export option of Indesign CS5 after that we make them comment enable using Adobe acrobat 9 pro software.
Our client freelancer used Adobe Reader XI (11.0.07) which was updated on 22/05/14 to give comments on that PDF.
Once again our client wants to add some more comments in the PDF using Adobe acrobat 9 pro. But during this the file got corrupt. Below is the statement given by them.
"I received the proofread corrections back from the proofreader last week but there were still a few extra corrections to mark on. However when I attempt to mark these extra corrections on the proofs myself and then save it, the pdf immediately becomes corrupt and unreadable. IT were unable to solve the issue but they said that it might be some sort of font error. Could you look into this to see if this is an issue. It might simply be the case that it is a very large file and so it has become corrupt for that reason. I’ve never had this happen before on one of my files though, could you let me know if you have heard of it happening or if you know of any reason why this might happen?"
We are also trying the same process at our end but there is no such problem face by us. We even try to add the comment in the PDF worked by freelance using Adobe reader XI but everything goes fine.
We are able to add comment in Adobe acrobat 9 Pro and no file corrupt issue face by us. Is it possible for you to let us know the reason of such problem at our client end. Size of PDF is 178 MB.
Even in acrobat reader XI we dont face any problem in adding comments.
Is anyone let me know why our client is facing this type of problem.

Answer 1

Linda, I'm wondering if there's some "conflict" being triggered because you're using both Win 7 and WinXP --
Specifically, I wonder if the two systems have off-kilter time stamps, and that's why FM is giving the "newer creation date" problem.
I don't quite understand what role the XP system has in your test, though -- can you not just use FM == and == make the PDF on the same Win7 box, make the comment on that box, then import the comments?
Understandably you will probably eventually need to be able to import comments from all sorts of other systems, but for troubleshooting could you try making the full create-comment-import cycle on the Win7 box only?
If that does work, then you might see of you can set the system time on the XP box to be somewhat slower than the Win7 box, and re-try with the XP box in the mix.
Edit: changing the system time clock is suggested only as a testing procedure, to see if we can isolate the exact cause, I'm not suggesting that in order to work reliably all your reviewers would need to synchronize their systems :-)
Sheila