Carbon Copy Cloner requires OS X. CCC will not run on Windows.
Carbon Copy Cloner 4 is the latest version available. Users running Mac OS X 10.8, 10.9, or 10.10 should use this version of CCC. If you are having trouble downloading CCC from the link above, try this alternate download location.
Yosemite support: Carbon Copy Cloner 4.0.2 (and later) is qualified on OS X Yosemite.
Upgrading from CCC 3? CCC 3 licenses purchased on or after June 2, 2014 are eligible for a free CCC 4 upgrade license. CCC 3 Personal Use licenses purchased prior to June 2, 2014 are eligible for upgrade pricing. When you open CCC 4, it will automatically retrieve your new license or an upgrade coupon that you can use to purchase CCC 4 at 50% off.
Carbon Copy Cloner 3.5.7 is compatible with Snow Leopard, Lion, Mountain Lion, and Mavericks. Note that while this version of CCC will work on Mountain Lion and Mavericks, we recommend that Mountain Lion and Mavericks users upgrade to CCC 4. We will continue to offer limited support for 3.5.7 on a case-by-case basis, but we are no longer actively developing this version.
Why doesn't CCC 3.5.7 work on Yosemite?
Unfortunately I was not able to make CCC 3.5 work on Yosemite. Despite months of research, the list of deep-rooted problems with CCC 3.5 on Yosemite was too long to be addressed in time for Yosemite readiness, so I invested my development resources in CCC 4 instead. For folks that might want more details on why that was the case, I posted an entry on our blog, Why doesn't CCC 3.5.x run on Yosemite?.