Several long-term, experienced CCC users have reported basically the same problem: not all CCC backups are bootable. This is true following all directions, and reviewing troubleshooting boards. Our non-bootable backups started after installing OS X 10.3.4, and continues with OS X 10.3.5. Everything works fine, but the clones are no longer bootable, including internal and external drives, and on three different systems (G3 PowerBook, and G4 Desktops). The systems hang at startup with a blue screen and rotating radial line ball. All data appears copied correctly.