I have 21 slides. Latest everything (OS, Keynote etc...). No problems until I added some more pictures and now I get the same message.
Every time I try to save my file, I get "Couldn't auto-save document".
Honestly, this is so pitiful, by a mega rich company that tells us continually that they produce amazing stuff. Yes, Keynote truly is amazing. Powerpoint does not have these amazing problems. What is auto-save doing anyhow? There are no setting for auto-save, nothing in the help files. I am not asking it to auto-save. I just click "save" but uncle Apple knows best, and fails. Sounds like my wife's iPad iOS 8.0.2 in which Pages is really unstable. I guess Apple cannot afford proper testers.....?
I can duplicate the document and it seems to save that new file fine.