Artboards missing after save, can't get them back
Hi, using CC 2017.
I had a file with 4 artboards and 20 layers for each language. It was a .pdf that I created originally in Illustrator and only used in Illustrator.
I saved it today in the usual way and somehow now when I open the file in Illustrator, it won't open all the artboards (it asks me which page I'd like to open), and it's removed all the layers that were hidden.
I have tried my legacy files in dropbox to no avail. Renaming to .ai, etc.
I can see that the file size hasn't changed, so the information must still be contained in the file.
How do I get my artboards and layers back?
