Hey folks! I'm sure this topic has been beaten to death and beyond. I've spent quite some time researching this myself but I wanted an answer to the doubts/questions I now have. But first, basics: I have a 3yr old Aperture 3 library which is 373gb in size (on a 750gb MBP). I do not have a backup and all pictures are managed. My general workflow is: 1) Shoot landscapes or astro (star trails/stacks), holiday trips [normal pictures are JPEG, astro pics are RAW) 2) Import them from the SD card into Aperture directly 3) Delete ones that I don't want to reduce the number of pictures 4) Export JPEG versions for star stacking, time lapsing or panorama stitching 5) End of workflow. So, now, I'm running out of space on my drive. I gather that the best option to free up space is to relocate the masters. But, I haven't backed up my Aperture library ever and want to start it. Questions: 1) Can I treat the "relocate the masters" option as a backup? 2) After relocating the masters, can I still use Vault as another option to backup the referenced images/versions left over on my MBP? Any help would be great!