I'm getting a serious headache from this issue. I'm trying to find a simple way to annotate my textbooks and keep them synced between my macbook and iPad. After days of struggling with this, someone finally suggested on here to get PDF Expert and sync my textbooks using iCloud instead of Dropbox because the latter takes ages to upload. I followed the steps, turned on iCloud on both devices, moved a file from PDF Expert and now I can't find it on my Macbook. Turns out I don't have some folder called "Mobile Documents". I have OS X 10.8.5. I googled and found out a few people have the same issue. Is there an easy way to fix this? I don't understand programming and really don't have the time to go look for someone to fix this AND pay the extra change. At this point I'm just contemplating going back to the brick and stone method and print all my textbooks and carry them with me to classes. Sick of this... any ideas?! Please?!