Domande frequenti

A volte i componenti hardware muoiono di una morte lenta e fastidiosamente imprevedibile. In un momento sembra che sia possibile copiare i dati su disco e utilizzarlo normalmente. Il momento successivo si verificano errori apparentemente casuali, interruzioni, blocchi, il volume di destinazione "scompare" nel mezzo di un'operazione di backup, blocchi del Finder e altri comportamenti strani.

Configuration files for privileged helper tools are placed in the /Library/LaunchDaemons folder on your startup disk. CCC never touches this folder directly, rather it uses the macOS "Service Management" service to install and load its helper tool configuration. If the permissions or ownership of this folder are incorrect, however, the Service Management daemon (smd) will fail to install the helper tool configuration, and this service offers no recourse. Often the helper tool installation will fail with a nondescript error, e.g. "CFErrorDomainLaunchd error 2".

If you boot your Mac from a backup volume, CCC will be started upon login to ask whether you'd like help restoring from that backup volume. Sometimes, though, this offer is made when you're booted from a production volume, not a backup. CCC makes this assessment based on your currently-defined backup tasks. If you used CCC to migrate from one drive to another, then the task that you used to perform that backup will still be present on your new startup disk.

CCC offers hourly, daily, weekly, and monthly scheduling options, which suits the needs of most users. Some usage scenarios, however, demand higher frequency backups. For example, photographers might prefer to have their SD cards offloaded to a tethered computer every 5-15 minutes during a photo shoot. When the shoot is complete, though, the backup task should not run at all. Special cases like these demand more flexible execution options, which can be achieved by leveraging CCC's built-in command-line utility.

CCC can run backup tasks while the system is running on battery power, but will not (by default) start automated tasks when your laptop is running on battery power. Backup tasks generate a lot of disk read and write activity, and that can run your battery down. Additionally, macOS tends to aggressively put the system to sleep when it's on battery power, causing task completion to be deferred until the system is awoken.

According to ObDev developers, it is crucial for Little Snitch to avoid unnoticed ruleset changes. Little Snitch therefore has numerous mechanisms to detect whether it is using the exact same ruleset file, as in, on the same volume and at the same physical address on that disk. This sort of mechanism makes it impossible for Little Snitch to use the ruleset on the booted backup volume without physical intervention from a user at the system (thus the dialog asking if it's OK to use the current version of rules or to use a default ruleset).

No. Copying a Time Machine backup volume with anything other than the Finder is not supported (by us, nor Apple); CCC specifically disallows copying anything to or from a Time Machine backup volume. Apple does not document a procedure for making copies of Time Machine volumes.

CCC always examines the files on the destination to determine if they already match those on the source. If you have a volume that is virtually identical to your source, CCC will copy only the items that are different between the two volumes.

Note: The topics in this article are not relevant to APFS-formatted destination volumes that have CCC snapshot support enabled. For those volumes, CCC leverages snapshots to implement the SafetyNet functionality, and the snapshots aren't affected by any of the shortcomings described here.

CCC makes bootable backups specifically to avoid this kind of situation. When you have a bootable backup, you simply boot from that, then restore everything to a replacement disk or the original disk. One step, minimal time, couldn't be easier. Occasionally people get into this sticky situation though -- I have a backup of everything in a disk image or in a folder on the backup volume, there's a clean installation of macOS on my replacement disk, now how do I get everything back to the way that it was before?