Convert .cdr to .iso on Mac OSX Leopard

Mac OSX Leopard creates disc images in .cdr format by default. If you need a standard .iso file — for use on Windows, Linux, or with other burning tools — here is the quickest way to do it using only tools built into the OS. No third-party software required.

Credit for this method goes to Andy Peters — the original post is no longer online but the technique remains valid.

Step-by-Step

1. Open Disk Utility and highlight the CD in the drive.
2. Click New Image in the toolbar.
3. Set Image Format to DVD/CD Master. Name it and save it wherever you like.
4. Wait for the image to be created — this produces a .cdr file.
5. Open Terminal.
6. Navigate to the folder where you saved the file:
   

   cd ~/Desktop

7. Run this command — replacing FILENAME with your actual file name:

   hdiutil makehybrid -iso -joliet -o FILENAME.iso FILENAME.cdr

8. Done — your .iso file is ready to burn or use anywhere.

Notes

• The -joliet flag adds Windows compatibility to the ISO — useful if the disc needs to be read on non-Mac systems.
• If you only need to burn on a Mac, you can skip the conversion entirely — Mac natively supports burning .cdr files directly.
• This works on Mac OSX Leopard (10.5) and later versions of OSX/macOS.