Comment by cm2187

Large companies do have this sort of backups. But cryptolocker's target population is individuals and small businesses. Having to manually plug and unplug a drive every day is an unreasonable burden for this population, and may not even help if the drive is connected while the user is unaware of being infected. WORM NAS volumes or NAS volumes that do incremental snapshots behind the scene are a better solution but I am not aware that major consumer NAS manufacturers (Synology, etc) offer that.