What does losetup: could not find any free loop device mean and how do I fix it?
Loop devices are used during the build; there probably aren’t any free if you’ve aborted several builds. Something like: for l in /dev/loop* ; do losetup -d $l ; done should rectify the situation (assuming all loop devices in use were created by lh_build; if in doubt, check the contents of each loop device before deleting them with losetup -d).
