At the university, I saved a huge project of mine containing a density map and multiple (!) rigid-body fitted pdbs.Although this system is a 32-bit Kubuntu 8.04 only (4 Gig of RAM installed), I observed the same problems with my 64-bit SUSE 10.3 (4 Gig of RAM installed as well) at work.Creating this project took me two days in total, so I really would appreciate any suggestions from you ...