Backup and archiving settings

Carbon Copy Cloner maintains a list of certain files and folders that are automatically excluded from a file-level backup task. The contents of this list were determined based on Apple recommendations and years of experience. The following is a list of the items that are excluded along with an explanation of why they are excluded. This list is not (yet) configurable.

Carbon Copy Cloner will save previous versions of modified files, as well as files deleted since previous backup tasks to an archive folder at the root of the destination. If left unmanaged, this archive folder would eventually consume all free space on your destination volume. To prevent that from happening, CCC offers three different ways of managing the contents of the archives folder. You can customize this behavior by clicking on the "Customize these settings" button in CCC's main window (choose a source and destination if you don't see that button).

CCC offers several options for handling files and folders that reside exclusively on your backup volume. By default, CCC will archive files and folders that exist exclusively on the destination. In a typical dedicated-backup-volume scenario, these items would likely be files that had been previously backed up, but then deleted from the source volume. You can customize this behavior by clicking the "Customize these settings" button.

CCC conveniently lists the contents of your source volume when you select it in the Source menu. Next to each item in this list of "Items to be copied", there is a checkbox that, when unchecked, indicates that an item should not be copied to your destination volume (unchecked items will also turn red to indicate that they are excluded). Each folder in this table has a disclosure triangle, just like in the Finder. Click on the disclosure triangle to reveal the contents of a folder, then you can continue deselecting items to be copied, if desired.

CCC offers three options for handling files that have been modified since a previous backup. By default, CCC will archive modified files to a folder named "_CCC Archives" at the root level of your destination. You can customize this behavior by clicking the "Customize these settings" button in CCC's main window.

Settings in the Advanced Settings panel are helpful in specific situations, but not generally recommended for routine use. Some of these settings involve more risk, so please use them with caution, and don't hesitate to ask questions at the CCC Help Desk if the explanations below are insufficient for your particular scenario.

If enabled in CCC's preferences, CCC will indicate if the source and destination volume selections qualify for a block-level copy. During a block-level copy, CCC unmounts the source and destination volumes, reformats the destination volume to match the source, then CCC proceeds to copy blocks of data from the source to the destination. Once all of the blocks from the source have been transferred, CCC then reads all of the blocks that were written to the destination and calculates a checksum. This checksum is compared against a checksum of the source volume.