I have this problem, all Disk images ( .dmg ) don’t work. When I double-click one, Dick copy run and say it’s a success but I get a “unreadable disk” error message with continue, eject and initialize as the options. With continue, the disk is unavailable but I can see it in Disk Utility and even check it ( appears to be ok ).

in terminal, I tried ” mount -t hfs /dev/disk2 /Volumes ” , /dev/disk2 being the device for the disk image as reported by the Console and Disk utility but it says : “hfs : device busy “.

I’m a bit out of ideas on this. Does macosx work like windows and we will have to get used to reinstalling the system software every months ?

Have you installed any unauthorized hacks lately? If you installed any system hacks to your system it can affect the way disk images are mounted and read.

I had this problem with older version of the Disk Copy utility and OS X, but since upgrading to OS X 10.0.3, and 10.0.4 since then, the problems have suddenly gone away.

Booting into Single User Mode (restart holding down Command + S) and then running a File System Check (fsck) to see if there are any problems might help.  To do that, once you boot into Single User Mode, type “fsck -y” without the quotes, and keep typing that until you get the system to report “Volume appears to be OK.”  If you get something that says “***FILE SYSTEM MODIFIED***” run fsck again and again until you get the ‘OK’ response, then type “reboot”.  That MAY help, and it is actually one of the few things that people can do under OS X, easily, to troubleshoot and repair some problems.

Reinstalling the OS should not be necessary.  Try this, if you have not already, and see if it helps.

Also, try to mount a variety of images.  Could always be a problem with the image files that you are using.  If this is all painfully obvious, I apologize.

I’ve tried the fsck -y in single user mode and it still don’t work. After further tests, perfectly working cd-rom ( under os9 ) don’t work either. They do the same thing as disk images. I’m beggining to suspect that everything using hfs ( not hfs+ ) doesn’t work.

Disk images and cd-rom can be used by mounting them manually in terminal mode with “mount -rt hfs /dev/disk2s1s2 /tmp/aa” for cd-rom or “mount -rt hfs /dev/disk2 /tmp/aa” for disk images.

Anyone with ideas about what could be wrong ?

For the unauthorized hack thing, the only one I use is Docking Maneuvers witch enable the dock pinning and orientation setting.

Is your filesystem HFS or UFS? UFS has been known to be very problematic with this release of OS X. If not will anything HFS mount? Any disk image like a backup? If not it may well be a corruption problem.

On 2001-07-10 12:57, dcantrel wrote:
Is your filesystem HFS or UFS? UFS has been known to be very problematic with this release of OS X. If not will anything HFS mount? Any disk image like a backup? If not it may well be a corruption problem.

My filesystem is hfs+. And every CD’s does the problem I explain, including original Macos9 cd. And every installation image.

See the following Apple Knowledge base article:

Mac OS X 10.0: Removable Disks Do Not Appear (Mount) on Desktop
Article ID: 106345

I am having this same problem in OS X 10.1.4, and I have no idea how to fix it besides just doing a reinstall. Very frustrating.

Whenever I insert a CD or mount a disk image, the Finder says “This volume is unreadable by Mac OS X” and then gives me the option to ignore the disk, eject it, or initialize it.

Nothing worked using mount or hdiutil, but if I restart in another Mac OS X partition or Mac OS 9 partition, everything works fine.

Also, if I use the Disk Utility to unmount one of my hard drives other than the startup disk, there is no way for me to re-mount it; I get the same “this volume is unreadable” error, even though a minute ago that volume was working fine.

I have seen two or three other mentions of this problem on the internet, but no one seems to know of a solution.

  Alex Williams

I have the same problem; I noticed it first when I started trying to mount an ipod and getting that error box (I actually clicked “initialize” thinking it just wanted to format the storage space, but that wiped the system software).  No smi’s or dmg’s will mount.  Was at 10.1.2, now I’m at 10.1.4 and same issue.

Mike H