Fix comment feature!
When you spend hours reviewing and adding comments, no matter how many times you save as you go, Adobe Acrobat Pro DC doesn't actually save the comments. When you open the file up later your comments are missing like you never made them. sometimes it saves somethings, most of the time it doesn't save anything. worthless program!
Rob King commented
Adding a sticky note seems to work. I just close the file when I'm finished and it asks me to save. It saves it every time.