the operation could not be completed because an unknown error occurred. [! Now]

[pele2921301923124]

"the operation could not be completed because an unknown error occurred. [! Now] "

The problem occurs when saving better quality png files

[Ton Frederiks]

Maybe you have reached a limit. At what resolution and at wat pixel dimensions are you exporting?

[Mateusz30397322cml3]

2400ppi, I need such high quality graphics for professional prints

[Monika Gause]

You could save the AI file with PDF compatibility and then openthat in Photoshop at the desire resolution and save from there.

Or send a PDF into print.