Xcode no mountable file systems dmg mac sierra

broken image

Here's a paste of what I get when I try to mount the DMG from the command line. I recently updated to 10.5.8 in case that's relevant. I've also tried re-downloading this image several times using several different programs. The disk will not mount from Disk Utility either (nor does attempting to verify or repair it from there have any effect). My google-foo reveals only some isolated incidents, and the repeated suggestion to reboot (I have, twice).

broken image

The error is always 'no mountable file systems'

broken image

I tried another image from the same company, and then a number of images I had laying around from other software. I downloaded a DMG of some commercial Mac software (CSSEdit) but I found that the DMG wouldn't mount.