Note that shutting off your Mac should never be required, at
most you would have to turn off one of your external devices.
I should also note that I see this same kind of behavior with my
own G-Drive enclosure, and it is not limited to CCC. There are
times that my computer won't turn on at all if the G-Drive is
attached, and times when it hangs altogether (even if CCC is not
running). Detaching the enclosure from my Mac breaks the hangs, and
things continue to work fine once I reattach it (for a while
3 Posted by Marie-Louise Gariépy on 20 Dec, 2011 03:15 AM
My general problem with CCC is that about everytime (really, like 80% of the time) the backup does not complete. This is not really handy. Either there is a real problem with my system (I am not denying that possibility) or your software is not performing well...
I am always backing up from an external drive to another. My master drive is always a G-Drive. The other one is a cheaper brand. Note that if this would happen only with one clone drive, I would suspect this drive but I do use 6 different clone drives (I have 3 master drives and 2 clone drives per master drive, hence 6).
Note that I do not use my computer when it is backing up. I tend to forget to turn off the airport (so dropbox might be copying files once in a while, but never on the external master and clone drives). I would doubt dropbox to be the problem since I do recall the backup process freezing when I am sleeping (therefore not using dropbox on another computer).
Next time, I will try to disconnect the drive (since stoping the process does not work). I think I have tried that before - beside it does not seem a good practice to disconnect a drive while it is still running, no?
In nearly all cases where a backup task hangs, the underlying
cause is a hardware malfunction or an inability to read the media
(e.g. bad sectors). When a hang occurs that affects the entire
system responsiveness, I have yet to find a case where the problem
was anything other than a hardware problem. Individual applications
can't hang the whole system, Mac OS X doesn't work that way. A
single application can do something that elicits that
behavior, but only hardware (or maybe the kernel) can cause the
entire system to become unresponsive. More times than not, it's a
deadlock in the system bus (e.g. Firewire or USB), and breaking
that deadlock will get things moving again.
it does not seem a good practice to disconnect a drive
while it is still running, no?
I wouldn't recommend it if you were actively writing data to the
disk. If the whole system is hung, though, and the alternative is
to turn off your computer, the effect on the disk is the same.
Filesystem journaling prevents most problems that would come as a
result of disconnecting the disk in this manner, but if you aren't
actively writing to the disk, I wouldn't expect any trouble at
My master drive is always a G-Drive. The other one is a
cheaper brand. Note that if this would happen only with one clone
drive, I would suspect this drive but I do use 6 different clone
drives (I have 3 master drives and 2 clone drives per master drive,
I still suspect the G-Drive, only because I have personally seen
the exact same issue with this device, and I have seen several
reports of the same behavior (a few related discussions are listed
below). If you could isolate the enclosure type out of the
scenario, we might be able to make a more definitive conclusion.
Are all of the enclosures attached to your Mac at the same
I would also like to take a look at your CCC.log to see if there
are any other problem indicators. Can you submit that to me for
review? The easiest way to do this is from within CCC:
Choose "Report a problem" from the Help menu
Click on the "Submit Logs" tab and review the information
Click on the "Submit Logs" button
Update this discussion to let us know that you've submitted
your logs, and please note the submission ID at the bottom of the
Submit Logs tab.
I see that you were able to break the cycle in your two most
12/29 00:34:11 [INFO] Volume unmounted: "PROJETS 3 clone A"
12/29 00:34:11 Aborting clone, destination disk has disappeared
12/29 04:42:42 [INFO] Volume unmounted: "PROJETS 3"
12/29 04:42:43 Aborting clone, source disk has disappeared
So that confirms my suspicion that there was a hardware deadlock
(if CCC was hanging on anything else, e.g. an internal bug, it
would have continued to hang despite the source/destination
Back in September there were some media errors on PROJETS 2 and
some filesystem issues on PROJETS 2 - CLONE B. It looks like a
mount/unmount resolved the problems on the backup volume.
Other than that, I don't see any indication of problems with the
other devices (your logs go back to August). It seems that the
problems are limited to (probably) the "PROJETS 3" device. The hang
seems to be fairly reproducible. Can you run any of your other
backups tasks manually to see if they elicit the same hang on the
other hard drives?
You might also try swapping cables with one of the other devices
to see if that affects the task's ability to complete without a
hang. Cables seem fairly inert, but I actually have a USB cable
that causes some really strange problems. A backup task works fine,
but Disk Utility can't reformat a disk in an enclosure connected to
my Mac with this particular cable.