southerner

Cheers @Dan C, my specs are: Processor/RAM: Intel Core i7-6700 CPU @ 3.40GHz / 16Gb Motherboard: Gigabyte GA-B150M-D3H Graphics: Intel HD Graphics 530 Display: Philips 273PLPH 27" Am suspecting that since I don't have a specific, high-spec graphics card installed, the hardware acceleration option is probably inappropriate for me anyway? Hope this helps.

I can also confirm. In my situation it is simply when exporting to jpg after doing some editing. I have recently upgraded camera (Panasonic S5) and almost all my camera produced jpgs (at "fine" quality) are now producing these artifiacts after editing. Editing is usually only a little saturation plus brightness & contrast. Incredibly frustrating until I researched and found this forum topic. It would also happen on my old Panasonic G85 but only occasionally when doing complex editing. I've just turned off hardware acceleration and problem seems to have gone away. Up to now I have had to use Merge Visible multiple times across the various adjustment layers to produce two images, both with artifacts but in different places. Then I copy clean cutouts from one of these images to the other so as to get one clean image. Then export just that clean layer. Completely messy and frustrating so this "solution" is much appreciated, thanks. However it would be nice to have the problem fixed