Scratch Disk error on opening file. Scratch disk not full. Opens on Mac OS. no issues.

I have already done what you have suggested, thnak you.  The scratch disk error happens on generative fill or any other intensive task.  There is a dedicated 7TB sractch disk.   Once in while the disk is half full.

Just noticed you have two GPUs. That's always a problem.

Photoshop uses the GPU for actual data processing. It's not a simple one way downstream flow like it was in the old days and still is in simpler applications. You can't send data to one GPU and get the result back from the other. So there can only be one GPU in this equation.

The official advice is to disable one.

All in all you have a lot of non-standard configuration here, all of which can cause problems, and you really need to eliminate that for any efficient troubleshooting.

I would still take a long look at that AstroPanel and temporarily disable it.

Then 1) reset preferences and 2) uninstall/reinstall if it's still not working properly.

If you do get scratch disk warnings - those are usually real. Make sure you have 250 - 500 GB free space.

its one example of many.  Its been going on for months.  The system drive is raid 0 too. Its an itnel vroc system; full integrity.   There is an issue and it throews out this scratch disk error generically, then a program error if PS doesn't  crash.

The message is "program error", it doesn't say anything about scratch disk.

There are several unknown factors here that you need to take out of the equation first: I don't know what "Astro Panel" is, but third party plugins are always a prime suspect. Does it work if that is not loaded? Also, I see you're saving to RAID0. Does it work if you try saving to the system drive?