So I have a bad drive. I used disk drill to create a DMG of it. It took 10 days. On completion I immediately opened the DMG, ALL files present and accessible from mounted image! YAY! Closed down DD, shut down computer. Slept well. Came back, DMG mounted with error, all files (except a few folders) had disappeared from DMG. How is this possible? Scratch that, I don’t care why it happened unless it helps me get the DMG to mount properly with the original filesystem! What can I do?