Does cloud storage protect against ransomware?
Sync drives alone: no. When ransomware encrypts your files, the sync client uploads the encrypted versions, overwriting the cloud copies. What protects you is version history and point-in-time restore: true backup services (Backblaze, IDrive, Acronis) and providers with long versioning (Sync.com: 180 days) let you roll back to before the attack. Check the retention period; it is your real ransomware insurance.
Ransomware’s relationship with the cloud is widely misunderstood. The malware encrypts files on your computer; your sync client, doing its honest job, sees thousands of "changed" files and dutifully replicates the damage to Dropbox, Google Drive, or OneDrive within minutes. The cloud copy is now equally hostage. Sync is a mirror, and mirrors reflect disasters.
The defense is temporal: storage that remembers what files looked like before. This comes in degrees. OneDrive deserves credit for built-in ransomware detection with a one-click restore of the whole drive to a chosen date (within 30 days). Dropbox and Google offer per-file version history (30 days standard), workable for a few files, grim for ten thousand. Sync.com keeps 180 days of versions, a genuinely protective window. True backup services are built for exactly this: Backblaze (30 days standard, extendable to forever), IDrive (up to 30 versions per file), and Acronis, which goes furthest by actively blocking processes that try to tamper with its backup files.
CISA’s ransomware guidance (stopransomware.gov) adds the layer software cannot: at least one copy offline or otherwise out of reach of an infected machine, because sophisticated attacks hunt connected backups first. For a home, that means an external drive that is not always plugged in, or a cloud backup whose deletion requires separate credentials. Assemble it once: versioned cloud backup, offline drive in a drawer, and ransomware drops from existential threat to annoying afternoon.