Could not complete the PDF Presentation command because the file was not found.

Hi,

I am trying to export Artboards to PDF (2 artboards to be exact) and the program is not able to save the second Artboard so I constantly get the error "Could not complete the PDF Presentation command because the file was not found."

This is a file which I've used in a number of occasions and before and after last update of Photoshop Beta. I need to close the program and reopen to do it one by one. -.-