Hi Yatharth, Thanks for taking the time to reply. As mentioned in my initial comment, the issue is that the files had in fact been saved as I was working on them. Acrobat crashed and my saved highlights and comments were no longer there. It seems Acrobat is not a very stable platform for this type of work. I've noticed this is an issue going back many years for quite a few Acrobat users. It would be great if Acrobat worked on a backup solution so that when it crashes, crucial work can be retrieved. M ... View more