P: Export As error: "An unknown error occurred"

Found 2 different, recent cases of this happening:
https://community.adobe.com/t5/photoshop/export-as-issue-photoshop/td-p/10936950?page=1
https://community.adobe.com/t5/photoshop/quot-export-as-quot-thumbnails-preview-problem/td-p/1097360...
Might be related with Ryzen CPUs?

Im now having this/similar issue aswell. New PC, new, clean windows 10 pro 64bit system, everything up to date. I have observed even more weird things happening when i "export as" with multiple layers/artboards selected. Not sure if you would prefer me to re-write everything here, or just paste a link, but i think link to adobe forums is preferable: https://community.adobe.com/t5/photoshop/photoshop-cc-2020-quot-export-as-quot-multiple-layers-artbo...
An extract:
The "export as" window seems to be messed up for me. Some layers/artboards wont ever load, will keep loading till yellow mark with "unknown error". Whenever i use any options like "8bit png", "convert to srgb", change the format etc. the positions and their previews gets randomly messed up, changing previews even for what was previously properly displayed (like graphic "3" next to name of "e1" layer which should have "1" image preview):

Same issue since Update to 21.1 on macOS Catalina 10.15.3



Deinstalled and installed again. Did not solve it.

Update: tested in all available Versions back to 20.0.8
Issue exists in each.

"DISABLE EXPORT PREVIEW" THE settings option I've desired for over a decade.
What do we need to preview? not even sure why this isn't just a collapsible panel that uses the main dialog view.
Even when using slices.
Haven't found it useful once
100% waste of memory resources, at least start the previewer "fit to veiwer" 

Can take longer to preview than load PS and construct something new sometimes, we know what it looks like...

I get the same issues. Is this resolved?

OK Thanks. This issue has been logged.

Yes, it looks a lot like that.

Thanks Jeff for your detailed information!
So your issue is same as this?

I also have a PSD that causes the same issue.  If I don't wait after changing one of the configuration settings in the dialog box for the preview to build before changing another setting (like going from PNG to JPEG and then changing the JPEG quality from 100% to 77%) it fails with Unknown Error.  I see this happen more with large files where it takes more time to build the preview.

The thing I really would love is if Ps didn't rebuild the preview every time one of these configuration items is changed in the dialog box.  It doesn't happen on all of them (can add the copyright info without it causing the preview to update) but for most of them a change makes the preview rebuild and on these larger files that takes a long time.  I don't even use the preview for anything material.  Needs to not fail if you change something in the dialog box before the preview is done, but it would save me even more time if Ps wasn't working so hard to build a preview that I don't need.

How would you like me to send you the file?  I have a PSB that demonstrates the problem pretty well. 

Though I have to say that I upgraded NVIDIA drivers just released here in January 2019 and from Ps 20.0.1 to 20.0.2 and now I can't make the issue happen if I have some kind of selection made causing Export As to fail.  But if I change values in the dialog box before letting the preview complete it gives me unknown error.