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I have a knackered super-drive, and need to install software from a CD. However I do have backup images (as .dmg's) of all my install disks. Usually it all works fine, but with two particular installs it tells me to insert the CD into the drive. Is there anyway to fool the system into mounting the .dmg and make it look like a CD? I believe that Toast can do this, so it's possible. I was just hoping to be able to do it without forking out £80 - I could get an external drive for that (just not right this second)

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Have you tried using "Disk", in the /Applications/Utilities folder, to do this. It would be much easier than using the shell. – Mark Thalman Mar 1 '11 at 21:18
Under Windows I use Daemon Tools for this. Surely there's SOME OSX equivalent. +1 for good question. – Shinrai Mar 1 '11 at 21:21
If this languishes here, try migrating it to – Ian C. Mar 2 '11 at 3:49
@Mark Thalman mounting a disk image in Disk Utility does the same thing as double-clicking it. – Sidnicious Mar 11 '11 at 16:31

Unfortunately some programs are "clever" enough to spot the difference between a loop device and a cdrom. There's a third-party workaround for this at - it's not free, and I haven't tried it, but it does have a 2 week trial.

The short answer tho, is that for anything that actually tries to send commands to the drive, mount doesn't cut it; whether it be at the command-line or the UI.

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I can confirm that Toast can do this. If you aren't willing to pay for Toast I imagine that something like Michelle Six's answer will work. Try converting your .dmg to a .iso or something else.

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This worked great, thanks for the tip! – Brett Veenstra Apr 9 '13 at 10:26

it will depend on what you want to do, but if you need to convert the format to CD/DVD. I needed it to get VM Fusion to read a ISO file...

Go to Applications > Utilities > Disk Utility Go to File > Open disk image

The image will be loaded on the left

Select the image ISO

Look for the CONVERT in the header (between New Image and Resize Image)

Select image format and select CD/DVD MASTER.

Hope it helps

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The mounting methodology is probably not your problem. Most likely the problem is that something is looking at the file system. In general .dmg files are using the hfs file system where as CDs are using the iso9660 or UDF file systems.

A work around for this is to convert your .dmg into a .cdr here's how

  1. double click on your .dmg file to mount it
  2. open a terminal window
  3. sudo hdiutil create -attach -fs UDF -format UDTO -volname NewName -srcfolder /Volumes/CurrentVolume/ BrandNewImageName
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On Snow Leopard you can just right-click the .iso file and select "Open" from the menu. Then the disk will be mounted on your desktop just like opening a zip file.

If you need filesystem access just look in the /Volumes directory and you should see your image mounted as a directory there.

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The question specifically asked how to make it pretend to be a CD, not how to mount it. – Moshe Katz Dec 19 '12 at 23:40

You could try to mount the .iso to the mount point of your cd-drive with mount -o loop -t iso9660 /PATH/XXX.iso /PATH/TO/CD-MOUNTPOINT Just open a terminal and hack the command in. But i don't know where your cd's usally get mounted. You might to have superuser rights. Then do: sudo mount -o loop -t iso9660 /PAT/XXX.iso /PATH/TO/CD-MOUNTPOINT If it is a DVD the type might no be iso9660 in this case mount should throw an error with the right type.H

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This Linux answer is not applicable to Mac OS X. – Spiff Mar 7 '11 at 12:16

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