I am trying to export all my aperture files (master with xmp sidecar) in order to import into Lightroom. I am doing this by going to library, all images and the command-A to select all (about 23,000 in this library). I then go to export, and export with xmp sidecar into an empty directory. The export will proceed until around 11,000 files or so, and then it crashes and aperture closes. this happens over and over again. I've rebuilt the aperture database and it doesn't help. Any suggestions?