Macrium Reflect, rsync, Time Machine, Acronis Cyber Protect Home Office, Duplicati, SyncBack, GoodSync, Déjà Dup, BackBlaze, CrashPlan, AutoVer, Parachute, Personal Backup, FlyBack, Syncrify, BestSync, Snap Backup, Dmailer Backup, Dmailer Sync, Stellar Insta Backup, AutoArchive, Time Drive, Back it up!, Altarsoft Safe Backup, CascadePoint, Abakt, Ferro Backup System, Horodruin, IdleBackup are some alternatives to Back4Sure.