If you upgraded your Mac to macOS Mojave and have decided to downgrade for one reason or another, the procedure is usually pretty straightforward. Fusion volumes, however, introduce a complication. Upon upgrading to Mojave, a Fusion volume will be converted from HFS+ to APFS. If you want to downgrade to High Sierra (or any earlier OS), you must reformat that Fusion volume as HFS+. Because APFS Fusion volumes are not handled gracefully by High Sierra, however, the procedure is a bit tedious.
At its core, Carbon Copy Cloner is a product that is designed to make bootable backups of your Mac's operating system. In order for CCC to be able to make copies of system files, CCC needs to have the privilege of copying files that can't be read nor written by just any user – CCC requires elevated privileges to copy macOS system files. Likewise, CCC is often tasked with copying the data associated with multiple users. macOS prevents you from accessing files that belong to other users.
Some cloud storage service providers offer services that allow you to sync a local folder to "the cloud", and optionally choose to store those files only online, thus freeing up space on your hard drive. Some services that currently offer this functionality include:
CCC determines whether your destination volume will be bootable and indicates any configuration concerns in the "Cloning Coach" window. If you see a yellow warning icon in the Task Plan header, you can click on that icon to see these concerns. CCC will also present these concerns to you the first time that you configure a backup task to any particular destination volume.
If you're using an application firewall such as Little Snitch, you will see several outgoing network connections coming from CCC. We explain below what connections you should expect to see, and also explain why some connections that look unexpected are simply misreported by Little Snitch.
CCC will make external network connections for the following activity:
In bestimmten Situationen können Sie die Bedingungen oder Regeln, nach denen Sie Ihre Backups planen möchten, nicht mit einer Zeitplanung realisieren. CCC bietet daher Bedingungen zur Ausführung an, mit denen Sie die Ausführung von zeitlich gesteuerten Backups an weitere Bedingungen knüpfen können.
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).