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Managing previous versions of your files

 

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 for handling files modified since a previous backup

Files that have been modified since the last backup should be...

Moved to the archives folder

CCC will create a folder named "_CCC Archives" at the root level of your destination volume if it does not already exist (e.g. from a previous backup). CCC will then move any files that a) exist at the same path on the source and destination and b) are different in size or modification date into a time-stamped folder within this _CCC Archives folder. The folder hierarchy of your data will be preserved within this folder, so your files should be easy to find. The up-to-date version of the file will take the place of the previous version on the destination volume.

Moved to the Trash

This option is identical to the "Moved to the archives folder" option, except that the "_CCC Archives" folder will be created in the Trash rather than at the root level of your destination volume. This option may be preferable to the former if you want the option to access previous versions of your files, but want the convenience of simply emptying the Trash to quickly recover space on your destination volume.

Overwritten

This option disables archiving of modified items, though CCC will still perform an "atomic" transfer of these items to maintain the integrity of your backup and to mitigate risk. In an atomic transfer, CCC will first copy the replacement file to the proper folder on the destination, using a temporary filename. When the file has been successfully transferred and verified, the older version of the file will be deleted and the updated version will be properly renamed. This kind of transfer prevents a scenario in which an intact file on the destination could be replaced by a corrupted version from the source.

Don't modify files that are newer on the destination

By default, if a file exists at the same path on the source and destination, CCC will transfer the file if it is different in size or modification date. For a standard backup task, it is typically your goal to make everything on the destination look like the corresponding items on the source, regardless of which items are newer. In some cases, however, such as a restore task, you may prefer to transfer a file to the destination only if it is newer than the file that already exists there. This option is enabled when using the "Restore items from a backup" preset.

A note on archived bundle files

When CCC evaluates the items on your destination and determines whether they should be archived or left in place, it does so on a file-by-file basis. This poses a challenge for bundle files — files that are actually a folder of files, but presented by the Finder as a single file. As a result, bundle files (e.g. applications, some types of libraries, some custom file types) may appear in an incomplete form within the CCC archive folder.

Unless all of the components within a bundle file are modified, only the items that have been updated will be present. Incomplete bundle files are generally not useful on their own, but their contents can be. For example, if you accidentally deleted a photo from your iPhoto library, you would be able to recover that lost photo from the archived iPhoto library bundle. To reveal the content of an incomplete bundle file in a CCC Archives folder, right-click (or Command+click) on the item and choose "Show package contents" from the contextual menu.

Applications and portions of the OS generally cannot be restored from CCC archives

While it is possible to recover an older, complete version of a bundle file from the CCC Archives and complete backup (e.g. by overlaying the incomplete archived bundle file on top of the current backup of the bundle file), this is generally too tedious of a task to be practical for application and OS restores. CCC's archiving feature is not intended to provide a method for rolling back software updates, for example, OS restores should always be done from the complete backup at the root level of your destination. If you would like to make "snaphot" backups of your OS, choose "Choose a folder..." from CCC's Destination menu and choose a folder on the destination volume for the purpose of a one-time backup.