Is it safer to store files in the cloud or on your own computer?

The two options fail differently. A file on a single computer is lost to drive failure, theft, ransomware, fire, or a spilled drink, and consumer drives fail at rates that make this a matter of when rather than whether. A major cloud provider stores copies across multiple machines and often multiple data centers, so hardware loss is effectively not a risk. Against those threats, cloud storage is straightforwardly safer than a lone device.

The cloud introduces risks the local drive does not have. Your data is accessible to anyone who gains access to your account, which means a weak or reused password, a phishing email, or a SIM swap can expose everything at once, and account lockouts, whether from a forgotten credential or an automated policy action, can make your own files unreachable. The provider can read unencrypted data and may be compelled to produce it under legal process, and the provider's business decisions, from pricing to discontinuation, are outside your control. Sync services can also propagate a deletion or an encryption attack to every copy within seconds, which is why sync is not backup.

The defensible arrangement combines them. Keep working files synced to the cloud for convenience and hardware protection, secure the account with a unique password and a non-SMS second factor, and maintain a separate local backup, ideally one disconnected when not in use, so no single failure mode reaches every copy. For genuinely sensitive material, encrypt before upload using a tool where you hold the key, since provider-side encryption protects against outsiders but not against the provider or against anyone holding your credentials. Turn on version history where the service offers it, since that is what recovers a file after a bad sync.