Official website: http://www.bombich.com/software/ccc.html I have the previous version of the OS X cloning tool (making bootable copies of the operating system on external drives and vice versa) and it is very reliable. From the help file (colored): Carbon Copy Cloner 3 was completely rebuilt with a new suite of features to meet the growing needs of Mac OS X users. In addition to the fast disk-to-disk cloning, CCC is now a full-featured backup utility as well. Among the new features in CCC 3 are: Support for block-level disk-to-disk clones. Synchronization built-in, not bolted on. Support for backing up across the network to another Macintosh. Advanced scheduling capabilities -- choose what days to run your backups and how frequently they should run. You can also defer a backup if it starts at an inopportune time. Now you can create a scheduled task that backs up your data whenever you attach a specific hard drive or iPod. The ability to drill down into folders to select exactly what gets copied and what doesn't (you can drill down indefinitely). A more responsive interface and the ability to stop the clone. More accurate feedback during the clone. The ability to pick up where a previously aborted backup task left off. More information about your volumes are available within the CCC interface.