I'm transferring files from my old Aperture library on my old iMac, to a new library on my new iMac. Same version of Aperture. Should be no problems. Except, Aperture on my new iMac is a bit choosy about which files it will read.
I've imported images in batches, establishing a nice new library structure as I go. The export of images from the old Mac to a usb drive goes without any problems, but when I then import into my new Mac, every now & then a photo gets tagged as being an 'unsupported image format'. Quite how it can be unsupported by Aperture, when Aperture processed the damned thing in the first place, is beyond me.