I have observed that on a number of jobs since I installed CS5 that unless I select my print presets to Acrobat 6,7,8 or 9 for compatibility random graphics get dropped in the final. It seams to be logos placed in as AI files. I'm trying to choose Acrobat 4 as a preset because it's what I've told works best over the years, but I really need all the elements making up my image So I've been exporting selecting "Press quality" and Acrobat 7 - 9 in the compatibility box, which gives me a PDF that looks like it's all there at my end, but the printer sends me back a proof with the elements missing!? I've been watching Lynda.com videos all morning but I'm at a loss! The only pattern I can find are that the drops seem to be Ai files which really shouldn't and hasn't ever been a problem, and the fact that the jobs may have been started in CS4 - which , again - I'm thinking shouldn't matter! Right?!