[frank]

Ok, I might have 2 on an older Mac (not sure), but if you tell me which PP/effects you used I can try on my Mac with Silver Efex Pro 4 in CS6 to see if it shows similar tiling, or if it is resolved in the newer version.

 

 

Open a raw format image file with a grey/blue sky in CS6, in 16bits/chanel. Then open Silver Efex Pro 2, from the presets choose "010 Low Key 2", then I see the lines.

 

I tried 8bits/chanel in CS6, then I did not get the lines in Silver Efex Pro. So, if you use a jpg file as the source, you won't get the lines.

 

By the way, as far as I know the latest version of Silver Efex Pro is 2.