I was having this same problem when printing to my Canon Pro-100 from my MacBook Pro running Mac OS 14.6.1. I finally found a solution today. When the print dialog came up, there was a "Paper size" field which correctly was set to "US Letter". Howe...
FYI, I am having the exact same problem. Mac OS 11.6. Both Photoshop and Digital Photo Professional 4 behave the same way as you describe. The Print Studio Pro plug-in window is never displayed and Photoshop or DPP4 are hung. I see this same issue ...
