I should probably be addressing this question to the ERUNT developer, but people here are more responsive and explain things clearly. And I did read the tool’s “README”, searched this board, even gogled before posting. On the recommendation of TechSpot, I use ERUNT for registry backup, and have chosen the portable version, which does not require installation. Now, inside the backup folder C:\WINDOWS\ERDNT, in addition to the expected backup folders named after the date, I also see a folder named Hiv-backup. It has similar composition and is of no lesser size. I assume it has to do with registry hives. But what is this “Hiv-backup” folder really, of what use and when do I use it?