Member Avatar for debragail

I have been using Super Duper to create a bootable copy of my hard drive nightly. (This is in addition to using Time Machine.)

My hard drive has a capacity of 1TB of which 250GB is used.

My backup drive is a firewire 800 WD MyBook 1TB.

I noticed that my backups were starting to take hours instead of minutes and I cancelled the most recent after 19 days.

The logfile says:

(lots ommitted...)
| 08:17:26 PM | Info | /Users
| 08:18:53 PM | Info | Ignoring /.hotfiles.btree
| 08:18:53 PM | Info | /bin
| 08:18:53 PM | Info | /Library
| 11:17:40 PM | Info | Disk disk8s2 mount changed!
| 11:17:41 PM | Info | Disk disk8s2 vanished!
| 11:17:49 PM | Info | Disk (null) vanished!
| 12:11:26 AM | Info | Disk disk6s2 vanished!
| 12:11:28 AM | Info | Disk disk7s2 vanished!
| 12:11:29 AM | Info | Disk disk8s2 mount changed!
| 04:49:23 AM | Info | Disk disk8s2 mount changed!
| 04:49:24 AM | Info | Disk disk8s2 vanished!
(more of the same)

I have reformatted the back up drive.

I then tried a USB external drive with exactly the same results.

What's going on? There are no error messages displayed by the OS.

I have contacted ShirtPocket (developers of Super Duper) but no help yet.

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  • Latest Post Latest Post by dioioib

Dani AI

Generated

The log lines you posted show the external volume repeatedly remounting and disappearing — that’s the OS-level symptom, not SuperDuper itself. That pattern usually points to a flaky bus (cable, port or hub), failing enclosure electronics, a drive that’s starting to die, or power-management/driver issues on the Mac. is right to ask for the system’s disk/mount information; the next step is to isolate hardware from software and capture kernel-level messages while the problem happens.

Quick, practical diagnostic steps you can run now:

  • Remove hubs and connect the drive directly. Swap the cable and try a different port or a different Mac to narrow down enclosure vs. Mac.
  • While reproducing the problem, capture live system messages so you can see what the kernel says when the drive “vanishes”:
# watch kernel/system messages for USB/FireWire and disk events
sudo tail -f /var/log/system.log | egrep --line-buffered "IOUSB|USBMSC|IOFireWire|disk[0-9]"
# snapshot the bus so you can compare before/after disconnect
system_profiler SPUSBDataType SPFireWireDataType > ~/Desktop/BusSnapshot.txt
ioreg -p IOUSB -w0 -l > ~/Desktop/ioreg-usb.txt
  • Try a simple file copy or rsync to the external volume to see if the drop happens under basic I/O:
rsync -a --progress /path/to/large/testfile /Volumes/External/

Also check Energy Saver (disable “Put hard disks to sleep when possible”), and confirm the backup disk uses a GUID partition map and Mac OS Extended (Journaled) if you need a bootable clone. If the drive fails the above isolation (still disconnects on multiple Macs/cables), treat it as a hardware fault: copy off any important data, and share the bus snapshots and system.log excerpts with ShirtPocket or the enclosure/vendor when you contact them — those logs are what they’ll ask for.

Member Avatar for dioioib

debragail - thats some odd output. It looks like the drive is dismounting. I assume that /dev/disk6, /dev/disk7, and /dev/disk8 are all the same disk?
You can diplay more disk information by running the following commands in terminal:

diskutil list

and

df -k

Unfortunatly I cannot offer you a solution if this is the case. Super Duper might be sending a message to disount the disk in error.

I would be interested in seeing what your /Volumes folder looks like after this happens.

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