Mac Help - Convert and Burn Mac .dmg or .img to .iso Windows PC-Compatible Disk Image
- Open Disk Utility (located in Applications>Utilities folder).
- Drag your disk image into the left-hand pane (where all your drives are listed) of Disk Utility.
- Click on the file you just dragged into Disk Utility (should appear in the left-hand column).
- Click on the 'Images' menu, then choose 'Convert...'
- When the 'Convert Image' dialog pops up, select 'DVD/CD Master' from the 'Image Format' pop-up menu.
- Name your file, with '.cdr' at the end of the filename, then click 'Save.'
- Disk Utility will convert the file to an ISO image. After this finishes, replace the 'cdr' at the end of the filename (in the Finder) to 'iso'.
- Now, the disk should be burnable on a Windows PC (simply copy the file to your PC by either copying it across a network or using some other means of transferring the data).