Files/Autosave

I have a problem with the new creative cloud. As I am editing a document, I hit save and it says that another file is open, and that my document is now 'read only' Is this because of an auto-save? I've never had this problem, (15 years of no problems till now), this is very frustrating and causing me to have multiple names for a document I simply want to work on and save where it is on my computer!

Any help on why this is happening now, and how to fix it would be hugely appreciated!!

Thanks!

Diana