Does CCC have to be running for a scheduled task to run?
No. Once you have saved your tasks, you can quit CCC. Even if tasks are running, it's OK to quit CCC -- they will continue to run. A helper application, named "com.bombich.ccchelper" will be running quietly in the background, handling task operations. This helper application also loads automatically when you restart your computer, so you don't have to launch CCC again unless you want to make changes to your task configurations or scheduling.
What happens if no one is logged in when a task is scheduled to run?
The scheduled task will run whether someone is logged in to the machine or not. You can also log in or log out while tasks are running and the tasks will continue to run.
Will CCC run when the computer is turned off?
If your backup task is configured to "Wake or power on the system", CCC will schedule a "Wake or power on" event with the Power Management service and your system will turn on shortly before the task is scheduled to run.
FileVault exception
There is one notable exception to powering on the system for a scheduled task: If you have FileVault enabled on your startup disk, your computer would turn on, but it would not proceed past the FileVault authentication prompt. It is not possible for CCC to subvert this security feature, so the Wake or power on the system option will be disabled if FileVault is enabled on your startup disk. This limitation is applicable only when the system is turned off; CCC can wake a system with FileVault protection enabled and proceed to run a backup task.
Related Documentation
Will CCC run when my laptop's lid is closed?
If your laptop is running on battery power, the system will not wake while the lid is closed and CCC backup tasks will not run. If your laptop is plugged into AC power, then a CCC-scheduled wake event can wake the system to start your scheduled task if the lid is closed. See the section above for the settings that indicate whether a task can wake the system.
How is system sleep handled?
By default, CCC will not wake your computer when your tasks are scheduled to run. You can change this setting in the System Wake Or Power On Behavior section when scheduling a task. As long as your Mac is running on AC power, CCC will prevent the system from sleeping for the duration of a backup task.
Related Documentation
Why does my laptop sometimes go to sleep during a backup task?
If your Mac is a laptop, note that CCC will only be able to wake the system or prevent idle sleep if the system is running on AC power. CCC will attempt to thwart sleep while the system is running on battery power, but macOS may sleep the system anyway if there is no user activity while running on battery power.
Why does my screen turn on shortly before a backup task starts?
If your task is configured with one of the Wake the system options, CCC will schedule a wake event to occur 20 seconds before the task is scheduled to run. Whether the system is sleeping or not, macOS turns on the display when a scheduled wake event occurs, and there is nothing that CCC can do to prevent this. Additionally, note that if macOS detects an Apple Watch in the vicinity of the computer, it will attempt to use that watch to unlock the screen.
If you prefer that your display does not turn on, e.g. in the middle of the night, use one of the Run when the system next wakes settings instead to have CCC tasks run during macOS Dark Wake cycles (aka PowerNap, aka Maintenance Wake).
What if the backup disk is not available when a task is scheduled to run?
If your backup disk is attached to your Mac and unmounted, CCC will attempt to mount the backup volume, then proceed with the backup task if that is successful. If the volume cannot be mounted or is not attached to your Mac, CCC will, by default, report an error, then run the task immediately when the backup disk is reattached to your Mac. You can fine-tune CCC's handling of this scenario using the options at the bottom of the Automation panel.
Can I stop a backup task before it finishes?
Yes, you can stop the backup task at any time. The next time you run the backup task, CCC will copy only the files that have changed or were missed since the last backup task.
How can I disable/suspend a task?
If CCC's sidebar is not revealed, reveal it by choosing Show Sidebar from CCC's View menu. To disable a task, right-click on that task in the sidebar and choose Disable from the contextual menu. Use the same procedure to re-enable the task. If you would like to disable all tasks, hold down Command+Option and choose Disable All Tasks & Quit from the Carbon Copy Cloner menu. You may also disable tasks via the CCC Dashboard in the menubar.
Can I configure a task to run immediately after the computer is turned on?
CCC doesn't offer an option specifically to run tasks on startup. Running a task immediately after the system is turned on often introduces a lot of extra disk activity that will compete with the disk activity that occurs normally during system startup. Also, it makes less sense to run backup tasks after the computer has been off, because no files have been modified while the system was off. We recommend configuring backup tasks to run sometime toward the end of your work day instead. You can also configure the task to shut down your Mac when the task completes.
If your work day does not end at a regular time but begins at a fairly consistent time, then there may be one other option available to you. You can configure a backup task to run before your work day begins, and then configure that task to "Wake or power on the system". CCC will then schedule a "wake or power on" energy saver event, and then after the system powers on at that time, CCC will run your scheduled task. Note that this option is not available if you have FileVault enabled on your Mac's startup disk.