How can I convert a DMG to ISO on Mac OS X (preferably for free)?

Question

I have medical records within Windows software within a DMG disk image. How can I convert the DMG to an ISO format on Mac OS X? Is it possible to do it within Disk Utility or CLI easily, or do I need an external utility?

score 52 · Accepted Answer · edited Apr 12 '18 at 16:43

52

You can use hdiutil to convert from .dmg to .iso directly:

$ hdiutil makehybrid -iso -joliet -o [filename].iso [filename].dmg

Renaming .cdr to .iso is bad advice! An .iso has a slightly different format that allows PC users to play the DVD as well. A renamed file will work on macOS, but NOT on a PC.

If you have a .cdr and want to convert it to an .iso, execute:

$ hdiutil makehybrid -iso -joliet -o [filename].iso [filename].cdr

edited Apr 12 '18 at 16:43

Nimesh Neema

51,809

answered Dec 07 '14 at 13:26

Christian Tismer

665

3

Or you can just use the .dmg directly as input instead of going through .cdr. – dualed Feb 12 '15 at 17:37
yes, sure ;-) But please no renaming... – Christian Tismer Feb 13 '15 at 00:40
1

What would be the command to convert a dmg directly to iso just for completion sake of the question? – William Mar 20 '17 at 16:27
1

Does it work for creating a bootable Mac OS installtion iso image for VMWare? – Shayan Sep 28 '19 at 17:11
2

For anyone getting the error hdiutil: makehybrid: attach of disk image failed: 16, you need to unmount the image first (using Disk Utility). – Robert Jan 09 '20 at 09:24
If you get Segmentation fault: 11, try prepending sudo. – Nate Nov 10 '20 at 07:45

score 16 · Answer 2 · answered Jun 19 '13 at 03:17

16

Yes, Disk Utility can do this. Use Convert then select your dmg file. In the Save As dialog that follows, select DVD/CD master. Disk Utility will insist on saving the new ISO as a .cdr file, but it is really an ISO. You can rename it to .iso in the Finder, if you like.

At http://osxdaily.com/2012/07/18/convert-dmg-to-cdr-or-iso-with-disk-utility/ there are screen shots that walk through this process.

answered Jun 19 '13 at 03:17

mblakele

643

4

"it is really an ISO" is plain wrong. Seeing a .cdr from OSX, there appears to be no difference to a .iso . But you feel it after your DVD does not work on Windows. – Christian Tismer Dec 08 '14 at 13:57
4

I am still unhappy with the accepted answer. Both Sean and mblakele failed here, because an answer was accepted, that was only right for OSX users. But this will strike back, as soon as you try to use a renamed .iso in Windows. I think correctness is important, because wrong information should not be kept in the public, even if it's "just windows" ;-) – Christian Tismer Aug 05 '15 at 16:33
3

This is still wrong, today. What a shame! – Christian Tismer Dec 02 '16 at 18:41
@mblakele What convert button? Not seeing that on Disk Utility (version 16.0) . Am I doing this wrong, or is this answer just obsolete because of other software changes? – zipzit Jan 29 '17 at 17:19
@zipzit Apple likes to move things around from time to time. Try the Images menu, then Convert... – mblakele Jan 31 '17 at 04:58

score 2 · Answer 3 · edited Apr 08 '17 at 17:07

2

Would be the same:

hdiutil makehybrid -iso -joliet -o [filename].iso [filename].dmg

For example:

hdiutil makehybrid -iso -joliet -o output_file.iso file_to_convert.dmg

edited Apr 08 '17 at 17:07

fsb

22,799

answered Apr 08 '17 at 15:46

user232332

21
1

Does it work for creating a bootable Mac OS installtion iso image for VMWare? – Shayan Oct 01 '19 at 20:22

score -3 · Answer 4 · answered Apr 12 '17 at 15:57

-3

You must mount the cdr people.

answered Apr 12 '17 at 15:57

user233837

1

Welcome to Ask Different! Unfortunately, this doesn't look like an attempt to answer the question. – Glorfindel Apr 12 '17 at 16:23

How can I convert a DMG to ISO on Mac OS X (preferably for free)?

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