I created a layered illustrator file (CS5.5) for a client in Europe (illustrator 16, CS 6) and he couldn't access my layers. Is there a conflict between cs5 and cs6 for layers. Both Mac OS
Shouldn't be a problem. What exactly did you save? Does he really have Illustrator to open the file?
Are they actually sublayers and perhaps your client has things set to only show top-level layers?
How would the client set the file or illustrator to show only top-levels layers? Would it be in Layer Panel options or some other way?
Yes.. Layer Panel Options in the Layer Panel menu. You can decrease what the Layer Panel shows you... even though it's still there.