In attempting to use Disk Utility to make a .dmg image file archive of a volume on my Mac under Leopard, I got a new error message that did not appear before with Tiger: Unable to create "Drive To Backup" (Resource busy). Apparently in Leopard, you have to first unmount the volume you want to back up before you attempt to backup the image from the File » New » Disk Image From menu selection. [robg adds: A commenter on the queue review site notes he had the same problem, but believes it to be a bug (which he filed). In the interim, though, this solution works.]

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