Use more than one copy
Keep important data in at least two places, and for valuable information use a third copy that is separate from the computer. A common approach combines automatic cloud backup or sync with an external drive that is not permanently connected.
Backup versus synchronization
Synchronization keeps files consistent across devices, but deletion or corruption can also synchronize. Backup systems should provide version history or snapshots so earlier copies can be restored.
Test recovery
Periodically restore a few files and confirm that credentials, encryption keys and recovery codes are available. Businesses should document how a complete device would be rebuilt after loss or ransomware.