Q Whenever I open Disk Utility, it shows several disk images named decryptedFile.dmg in its sidebar. I keep deleting them, but the next time that I open it, they have returned. What are they, and how can I stop them?

A These are remnants of Adobe Flash updates, which you can safely unmount and trash.

The good news is that at least your automatic Flash updating is working well; with so many vulnerabilities appearing, perhaps you can never update Flash often enough! It is harder to know how to stop them reappearing, unless you physically remove the disk image files after each update, which can be a chore without reverting to manual updates, which could leave your system exposed.

Updated from the original, which was first published in MacUser volume 29 issue 8, 2013.