Frequently Asked Questions

Can I run backup tasks while my system is on battery power?

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.

Glossary of Terms

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Frequently Asked Questions about encrypting the backup volume

Can I use Carbon Copy Cloner to clone a Time Machine backup?

No, CCC will exclude the Backups.backupdb folder during a backup task because Time Machine backup folders contains Apple-proprietary filesystem devices. Apple's recommended procedure for copying a Time Machine volume is documented in this Apple Kbase article.

Frequently asked questions about the Carbon Copy Cloner SafetyNet

I want to back up multiple Macs or source volumes to the same hard drive

Backing up multiple volumes or multiple Macs to a single hard drive can be a messy proposition. If you back up each source volume to the same destination volume without some pre-planning, data from each source volume will be merged in a heap on the backup volume. Additionally, your tasks will archive or delete each other's backed up content. Carbon Copy Cloner can solve this problem! We lay out a few different scenarios and solutions below.

Identifying and Troubleshooting Hardware-Related Problems

Sometimes hardware components die slow and annoyingly inconsistent deaths. At one moment, it appears that you can copy data to the disk and use it ordinarily. In the next moment, you're getting seemingly random errors, hangs, crashes, the destination volume "disappearing" in the middle of a backup task, Finder lockups and other unruly behavior.

Some applications behave differently or ask for the serial number on the cloned volume. Did CCC miss something?

Some applications won't work when transferred to a new disk or when run on a different Mac. This has nothing to do with whether or how CCC backs up your data, it comes down to the serialization requirements imposed by the software vendor (i.e. their anti-piracy strategy). Some applications will work just fine, some will simply require that you re-enter your serial number, while other applications will require a reinstallation from the original install media or online reactivation via the vendor's website.

"The disk usage on the destination doesn't match the source — did CCC miss some files?"

There are a couple legitimate explanations for a mismatch between the capacities reported in Disk Utility. First, some system files and folders are excluded from a backup task either because they are regenerated every time your machine reboots, or they are not appropriate to back up or because they won't work properly on another hard drive or computer. The largest and most notable excluded item is the /private/var/vm/sleepimage file. The sleepimage file contains the live state of your Mac's RAM, so it will be as large as the amount of RAM that you have installed.

Can I back up one computer and use the clone to restore another computer?

Often, the answer is probably yes. However, there are some caveats.

Don't install older versions of macOS than what your computer shipped with

When you get a brand new Mac from Apple, it has a specific version of macOS installed on it, and further, a "build" that is specific to that exact model of Mac. If you install an older version or build of the OS, for example by cloning your older Mac to it, then it may behave unexpectedly, or it may not boot at all. If your new Mac is brand new, use Migration Assistant to migrate your data to your new Mac.