Guaranteed to get this error if anything is selected before doing Export As. Even if nothing is selected, I have to wait after EVERY change to the configuration of the dialog to not get that Unknown Error. Change from PNG to JPG, wait for the preview render. Change from Quality 100% to 77%, wait for the preview render. Change Width from native to 2048 (for exporting to social), wait for the preview to render. Change the Embed Color Profile to be enabled, wait for the preview to render. So long as I wait for the previews with every change, it works.
Windows 10 Pro, latest version of Ps in January 2019, video drivers fully updated (NVIDIA), 32GB of RAM.
Please, please. please just don't do the preview render!
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.
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.
"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...
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):
I tired the Technology Previews - "Enable optimized export as" and the only improvement is that the quick export will create an empty (zero bytes) file but the Export As malfunction is the same as before.
I am also having a problem when exporting, it informs that in the visualization an unknown error occurred and does not present the images to be exported. Also, I can't save the project. I have already tested other ADOBE programs and none of them showed errors, only photoshop. I have tried some methods, I have reinstalled the program and it remains.
Found the solution through adobe support, it's related to the new graphic card-based processing improvement in the program. Go to Edit>Preferences>Performance and uncheck the graphic processor option from there and relaunch the application. This will fix the problem with the heal brush as well.