turns out it WAS the ROOT user trick.
just did it very slowley and realised in the directory part of the root users dialogue box
I hadnt ticked one of the options properly. did it stepat atime logged in as root, used p5.5
logged back out,opened inmy user account...BOOOM PLAYBACK
Thanks to this forum for the previous non playback issue help
and just a wee note to say use that ROOT login trick if u ever have preview problems.
Might be out of your area of expertise, but since PrElements 9 has been released for the Mac, several users have experienced similar issues (not sure if they are exactly the same), but I wonder if this will help PrE users on the Mac, as well. Any help would be appreciated.
I have no clue about Elements.