I am utilizing managed files in Aperture 3. I have backup copies on external drives but I can only view the images on the external drive if the computer I am using has aperture loaded. Is this right or am I doing something wrong? My workflow is to copy the previous year, ie 2010, onto (2) external harddrive's, one kept offsite. Then sometime in the first part of year 2011 delete that archived year from Aperture, once I am not referencing frequently. This keeps aperture running smoothly and fast. Is managed preferred over referenced when using Aperture 3 or vise-versa?