Editing and Viewing between Preview and Acrobat

Hey all,

So I am having a client edit a PDF. He has a mac, and I use a windows at work. He edited the PDF using Preview, and then dropboxed it to me (not that I think dropbox would make a different), and then I opened it up on my Acrobat (windows).

When I opened it up, no text was there, but when you click in the field (using Acrobat), it shows the data the client entered only within that field, but when you click in a different field, it disappears.

So eventually, the client, went onto Acrobat and edited it again, and dropboxed it back and then I was able to open it.

Any idea as to why when it is edited on Preview, it won't work on Acrobat? Or is there any options in Acrobat to get around it? There are plenty of clients out there who will be editing on Preview, and I prefer them to not have to go out of their way to download Acrobat and make as default.

Thanks in advance!