P: Saving copy not saving over jpg file

Thanks Elizabeth.  Gave it a try and it seems to be working, so we'll see if the fix "sticks".  For others, this is the system Library folder:

System/Library/Application Support/Adobe

The Library folder may be hidden, a quick Google and that's easy to unhide.  Applied the change to the "Adobe" folder (adding me as a user with read/write permissions), and then going to the small gear icon (lower right) and applying those permissions to all enclosed folders.  

I finally just got this solved. I had to Chat with Adobe support here:  https://helpx.adobe.com/contact.html (there should be a speech bubble you can click in lower right-hand corner). I asked for "Troubleshoot a Product Issue" .... and I was eventually connected with the correct person. They screenshared my screen and solved the problem. It was a matter of choosing the correct permissions (see Leslie's post earlier)... but it was much more complicated than she explained, so sadly I don't think I would've been able to correct on my own.

Adobe online tech support is literally the worst.  don't waste your time.  It's a third-party outside the US.  very entry-level support.  

I spoke too soon.  As suggested, I changed the read and write permissions, worked for a day and now it is again saving copy and not saving over existing jpg.  

Please fix this issue, this is infuriating and makes the existing 'save as a copy' 'functionality' (read: hinderance) 10x more annoying

This solution does not work for me.

Same issue here also 😞

Just started experiencing the same issue. Ridiculous.

Same problem here. Posting to follow.

No, that does not work.  I can open an existing JPEG and tell it to overwrite JPEG and Photoshop it does not.  Instead it's this stupid copy-thing...  And, my images are already just one layer (the background layer), thus no layers to merge nor flatten.  Those options are grayed anyways.... well... because there is nothing to merge or flatten.