invalid ISO file created by disk util? In order to install Windows XP on Virtual Box at my new MacBook Air, I need to create an ISO file of my WinXP install CD. My Laptop (MacBook Pro / Lion) comes with the Mac Disk Util and that app can create ISO files from CD media. The problem was, after creating such a ISO file with that DiskUtil (using New image... -> CD/DVD-Master -> renaming to *.iso) that file wasn't readable by Virtual Box ;-( I've tried 3 various options but without any success.
After that, I tried it with command line only

dd if=/dev/disk1 of=WinXP.iso


But this file wasn't readable by VirtualBox too ;-( Also my muCommander, which can 'read' plain ISO files by step into like for directories, showing empty content. So something must be wrong with that ISO file. Finally, I come to a real weird solution: I've already has installed WinXP on Virtual Box at my MacBook Pro. I've installed ISOWorkshop, a freeware for creating ISO files from disc media. With that tool, I create the ISO file of the WinXP install CD (under WinXP on Virtual Box at MBP), copied that file to the MacBook Air, and use that ISO file for creating the WinXP VM under Virtual Box.... Oh my god ;-)
But the performance of the MBA is incredible: The whole installation was estimated with the famous '37 minutes' which was a  good approximation in the past for my machines. Today it was finished after 6 minutes !!!

Does anybody know, why the ISO files created by the Mac Lion Disc Utility are not 100% compatible with standard, or at least unusable for Virtual Box ?

Kind regards

Dominik
It sounds as if you created an empty disk image. To create an ISO/disk image of your disk you have to select the volume (selecting the drive may work too) in the left pane of "Disk Utility" and then click the icon "New Image" or «File» → «New» → «Disk Image from "XYZ your volume name"»  



For CD/DVD-ISOs make sure to select "DVD/CD master" as Image Format in the upcoming dialogue and no encryption.



Now your CD or DVD will be saved as an ISO-image with the extension .cdr - you can rename it to .iso if needed.