This was happening intermittently - lost a few pages along the way because of it - now it seems to be happening all the time - I can't save a document to save my life!
No matter how many times I try to save an unnamed Document via "Save As," it simply doesn't happen. Before it would "save" it with the name I entered...but the named document is blank!
But now it doesn't even do that: no matter how many times I "Save As"...it just doesn't happen - a .docx with that name never appears/doesn't exist. What I was trying to save still sits there as an unnamed Document. (A couple of times I closed that version expecting to see it saved as a named .docx, which didn't exist and I wound up having to rewrite it from scratch.)
I was able to save the document I'm currently working on in .txt format. Then I "saved as" the .txt version as a Word document - and for whatever reason it worked, I finally have a Word .docx along with the .txt version.
ANOTHER UPDATE: Just saved a new document as a .docx...& this time it worked! Go figure...