Hello there, Actually pro/e 32 DOES work under Windows XP 64 bits. I have installed that way, and it runs just fine, very little difference, much lower exit rate than before (pro/e 32 on WXP 32) At first we installed WXP64 and Pro/E 64, but that version of pro/e doesn't have the print to pdf option in the drawing enviroment, PTC simply decided not to put it on this version of pro/e. Anyway as we work with pdf drawing we had to roll back to Pro/e 32, but keeping the WXP 64 plattform in orden to make use of all the ram available (guessing it uses it all) But so far, no issues with this setting