High Sierra Testing and Known Issues

Baseline Testing

Troubleshooting slow performance when copying files to or from a network volume

Network performance is usually the bottleneck of a backup task that copies files to or from a network volume, but there are several other factors that can affect performance as well. Here are some suggestions for improving the performance of your NAS-based backups.

Why can't I eject the destination volume after the backup task has completed?

The disk Backup wasn't ejected because one or more programs may be using it.

Occasionally this annoying message comes up when you're trying to eject your destination volume. If CCC is currently using that volume as a source or destination to a running backup task, then CCC will effectively prevent the volume from being unmounted gracefully. If your backup task isn't running, though, CCC isn't preventing the volume from being unmounted. But what application is?

Where can I find CCC's log file?

It is our aim to have the Task History window provide the user with enough information to find and troubleshoot any problems they're having with their backup tasks. For debugging and support purposes, however, CCC logs its activity in the following files:

"The task was aborted because a subtask did not complete in a reasonable amount of time"

Occasionally a backup task can stall if the source or destination stops responding. To avoid waiting indefinitely for a filesystem to start responding again, Carbon Copy Cloner has a "watchdog" mechanism that it uses to determine if its file copying utility has encountered such a stall. By default, CCC imposes a ten minute timeout on this utility. If ten minutes pass without hearing from the file copying utility, CCC will collect some diagnostics information, then stop the backup task. Our support team can analyze this diagnostic information to determine what led to the stall.

Launchpad ignores settings created while booted from another volume

If you have assembled a custom arrangement of your application icons in the Launchpad application, you will discover that that arrangement is lost when booted from your backup volume. When you see this happen, you would naturally think, "Why didn't CCC copy the Launchpad settings?" In fact, though, CCC is faithfully copying the Launchpad settings. Here we'll show you how you can verify that, and also why the settings don't work while booted from your backup volume.

Help! My clone won't boot!

We're happy to help you troubleshoot your bootability problems. Before you ask for help, please try the troubleshooting steps below. If you're having trouble with the steps or have run out of options, please let us know how far you got, or how far your Mac gets into the boot process.

"CCC found multiple volumes with the same Universally Unique Identifier"

Occasionally a circumstance arises in which CCC presents the following error message before creating or running a backup task:

Uninstalling CCC

Uninstalling from within Carbon Copy Cloner

To Uninstall Carbon Copy Cloner, hold down the Option key and choose Uninstall CCC... from the Carbon Copy Cloner menu. When you uninstall CCC, CCC's privileged helper tool and all saved tasks will be immediately deleted. The Carbon Copy Cloner application file and CCC's preferences will then be moved to the Trash.

Uninstalling from within Carbon Copy Cloner

Antivirus software may interfere with a backup

Some antivirus applications may prevent Carbon Copy Cloner from reading certain files, mounting or unmounting disk image files, or, in general, degrade the performance of your backup. In some cases, antivirus applications can even affect the modification date of files that CCC has copied, which will cause CCC to recopy those files every time as if they have substantively changed. In another case, we have seen such software create massive cache files on the startup disk during a backup, so much so that the startup disk became full.