P: Saving copy not saving over jpg file

@ravnorodom I’ve also experienced the issue of layers disappearing while being moved. 

https://feedback.photoshop.com/conversations/photoshop/photoshop-save-as-creates-a-copy-file/60119d9aafca016da3030692

@mattrock1 Thanks for the info. Yes, animation codec is deprecated starting Big Sur (found out the hard way) and Apple ProRes 4444 is the replacement. I did think about hardware wise but I just bought my new Mac in 2019 so I am not planning to get a new one soon. Hardware upgrading (eGPU) would be my best route but not at the moment. I have plenty of RAM (64GB). I will stick to Mojave for a long while before moving on to the latest OS and Mac.

@ravnorodom Fair enough. I very rarely work with Video. I'm primarily print these days, though I have not encountered any images disappearing on screen when moving multiple layers at once in Photoshop, and I work everyday on very (very) large, high-resolution, multi-layered files. Nor have I experienced any critical bugs in Illustrator (also part of my daily workflow), InDesign, Bridge, or Acrobat. (as well as coding editors outside the Adobe suite for web work).

Perhaps there is a processor, RAM or graphics card or storage issue relating to your current work station? I'm not picking sides, but only things to consider if you're having all sorts of issues.

I replaced and upgraded my entire work station last year in order to keep up with the more and more demanding MacOS upgrades and workflows.

That said, I have no idea how isolated or not these issue may be in the video community. I'm simply trying to help eliminate all possibilities for a fellow frustrated Creative Suite subscriber.

As for the animation codec issue, sounds like Apple has moved on from an outdated codec that (according to some forum posts, anyway) most have moved on from prior to Apple jumping ship. Unfortunately at some point, everything becomes obsolete.

Create a new Lossless With Alpha Output Module template and choose Cineware or ProRez 444 and change the color option to Straight. The animation codec is very old, creates huge files, doesn't compress or decompress as well as either of those codecs. The Animation Codec is now deprecated and no longer being supported by Apple or just about anybody else. Adobe was just a little behind the curve with their presets.

You can get to the Output Module presets by choosing the Edit/Templates/Output Module menu and then edit any of the presets or create new ones. I have not had the Animation codes listed in any of my Templates for a long time. You can do the same thing if you are using the Adobe Media Encoder to render your video with an alpha channel. Just edit and save or create a new preset. 

[source: https://community.adobe.com/t5/after-effects/export-with-alpha-big-sur/td-p/11761305?page=1]

@mattrock1 In my case, there are more bugs than jpeg issue on Big Sur. I use almost all of the Adobe products including Premiere, After Effects, Illustrator, Photoshop, InDesign and more. On Photoshop in Big Sur, when you move a multiple layers at once the images disappear on screen. On Premiere, live scrub does not work at all and it's impossible to edit video. On After Effects, animation codec export is no longer support because Big Sur stops supporting it. That means my entire library of video that contains animation codec has to be converted to Apple ProRes formats. On Cinema 4D R16 (not an Adobe product), I can't even render animation footage. The list goes on and on. These will effect my work flow drastically overall. For me, it's worth going back but not for everyone who only use Photoshop or a minimal Adobe products.

@ravnorodom Could the same be said to NOT upgrade to Catalina if the issue persists with MacOS X as well as MacOS XI? I have Big Sur installed and haven't come across any more bugs than is typical or perhaps to be expected with previous new OS releases. There are many features and upgrades that work really well.

I hesitate to stay two OS's behind because Adobe can't (won't?) get a specific file type(s) on a select application to overwrite itself unless appended with "_copy" which it's able to do, due to an apparent miracle of sorts.

I reverted MacOS back to Mojave. It's the last OS that Photoshop works as it should be. No more "....copy. jpg". Here's the video that I followed if you are considering doing the same: https://youtu.be/C5W-l7K6W44

Catalina is where Photoshop issue started. Big Sur is the worst because there are more issues among OS itself and Adobe software. I think Adobe really don't give a crap about this jpeg issue at this point because there are so much craps to iron out in Big Sur and also preparation for future M1 chip based Mac. I threw in the towel. This jpeg issue slowed down my work flow drastically. Keep in mind that Big Sur is entirely a new OS (MacOS XI) under the hood. It targets the M1 Mac. DO NOT upgrade OS if Adobe is your bread and butter until most of the issues are fixed under this new OS.

Agreed, it means the problem has to do with the name rather than overwriting itself. Seems to me like a bit lazy from Adobe not to solve it if this is the case, or basically they don't give a ....

This is also an indicator that the issue isn't with Mac's OS as they state, but rather with Adobe's software as the file CAN be written over (and also works correctly with other file types or save methods as well as in other Adobe CC products).