The cloud is not a backup. OneDrive, iCloud, Google Drive, Dropbox and ProtonDrive are remote storage spaces, accessible over the Internet, whose primary purpose is sharing and availability, not the long-term preservation of your data. A backup, by contrast, must retain a file even after it has been deleted on the computer, and allow it to be restored later. Yet most of these services perform synchronisation: whatever you delete or encrypt on one side disappears on the other. To be truly protected, you need, in addition to the cloud, an external, offline copy.

What follows explains the difference between syncing and backing up, everything that can make your data vanish from the cloud, and how to use it without wrongly believing yourself safe.

Syncing is not backing up

Synchronisation is a mechanism that keeps the same versions of a file in two places in real time: software installed on your computer links certain local folders to remote folders, and any change on one side is immediately reflected on the other. This is what OneDrive, iCloud, Google Drive and Dropbox do.

Concretely, if you upload a file through the provider's web interface, it appears at once on your computer. And the reverse is true. If several devices are linked to the same account, your phone, your desktop computer and your laptop synchronise as soon as they are connected. The benefit is real and it is what appeals: your data follows you everywhere, and you share a file in one click.

But this benefit is also the trap. Since everything is placed on an equal footing on both sides, a mistake propagates. If you delete a file by accident, there is a strong chance it will also disappear from the cloud, and then from your other devices. Some services offer a recycle bin, but not all, and only for a limited time, often around thirty days. A synchronisation faithfully reflects the state of your files, mistakes included. It is not a memory of the past, it is a mirror of the present.

Everything that can make your data vanish from the cloud

Believing that the cloud backs up exposes you to several loss scenarios, which we see or know well.

Cause	What happens
Synchronised ransomware	The encrypted files copy themselves to the cloud, then to every device
Accidental deletion	The deleted file disappears everywhere through syncing
Suspended or closed account	No more access from one day to the next
Provider bankruptcy	Servers shut down, data inaccessible
Payment problem	Account closed and data deleted after a few days

The ransomware case is the most dramatic. A few years ago, we saw a company that stored everything on a OneDrive, with four or five workstations synchronised to it. An employee opened a fraudulent email, the ransomware encrypted the entire contents of his local drive, and that encrypted content immediately synchronised to the cloud, then to all the other machines. The client thought he had a reliable backup: versions in one place, versions in others, everything seemed covered. In reality, he had no backup at all. The entire dataset was lost, all the more so because he was slow to react and let the synchronisations continue.

The other scenarios are more discreet but just as real. An account can be suspended or closed for one reason or another, and if your data lives only remotely, with no copy at your premises, you lose everything. A provider can go bankrupt and switch off its servers. A simple incident with an automatic payment can be enough: past a certain deadline, the system closes the account and deletes the data. You need to know this: no cloud provider guarantees the restoration or the long-term survival of your data over time. It would be far too risky for them, so they contractually disclaim it. The responsibility always falls to the user, and it is up to them to set up a genuine backup.

No one guarantees your data: the OVH example

One event reminded thousands of companies of this reality. A data centre belonging to the host OVH, in France, caught fire in 2021. Customers trusted a major player, without knowing that the building was old: from what we understand, its floors and ceilings contained wood.

There was indeed a backup system, but it was located in the same building. The redundancy was housed in the same place as the original data, so the fire carried everything away at once. Thousands of customers found themselves in serious difficulty, some having permanently lost their data. The lesson is brutal: outsourcing your data does not exempt you from asking where, how, and above all whether a genuine independent copy exists elsewhere.

What the cloud does well, and the real remote backup

The point is not to demonise the cloud, which provides genuine services. A Google Drive or a OneDrive offers valuable availability, access to your data from almost anywhere, easy sharing with a third party, and sometimes versioning that lets you retrieve older versions of a file. Some even offer automated backup options. All these strengths deserve to be studied case by case, including when choosing a provider.

But these synchronisation services must be distinguished from genuine remote backup systems. The latter are less simple to set up than a Drive, because their aim is not daily access but pure backup. There you find concepts such as the cold backup, where data is kept offline, barely accessible, in large volumes at low cost, and recoverable through dedicated software. There you also find immutable versions, copies that cannot be modified or deleted for a defined period. This immutability is a formidable protection against ransomware and mistakes, precisely because even a compromised access cannot alter the backup.

In other words, everything depends on what the service you use actually does. A folder that synchronises in real time is not a backup, even if it is "in the cloud". A system of immutable or cold retention is one.

The right use: keep an offline copy, elsewhere

Even with a synchronisation cloud and a remote backup system, our recommendation remains the same: always keep an external, physical backup, offline and off-site. An unplugged drive or a tape, stored in another location, is what saves you when the account closes, when ransomware strikes, or when the data centre burns.

The cloud is an excellent tool for work and sharing. It becomes dangerous the day you entrust to it alone the role of last line of defence. Keep it for what it does well, but never stake all your data on an account you do not fully control.

Frequently asked questions

Is the cloud a backup?

No, not consumer services like OneDrive, iCloud, Google Drive or Dropbox: they synchronise your files, they do not back them up. A deletion, a corruption or a ransomware attack spreads to every copy. A genuine backup keeps independent versions that the source cannot overwrite.

Can ransomware reach my files in the cloud?

Yes. If it encrypts files synchronised on your computer, the encrypted version copies itself automatically to the cloud, then to the other devices linked to the account. That is why an offline copy, which the ransomware cannot reach, is indispensable.

Can you lose data stored only in the cloud?

Yes, in several ways: suspended or closed account, provider bankruptcy, a payment incident leading to the deletion of the account, or a deletion propagated by synchronisation. No provider contractually guarantees the restoration or the long-term survival of your data.

What is the difference between synchronisation and remote backup?

Synchronisation keeps the same versions in real time between devices and cloud, and therefore propagates errors. A remote backup keeps independent copies, often cold (offline) or immutable (impossible to modify or delete for a period), designed to restore after an incident.

What is an immutable backup?

An immutable backup is a copy that cannot be modified or deleted for a defined period, even with a compromised access. It is an effective protection against ransomware and mistakes, because the copy remains intact whatever happens to the source.

Should you keep a backup in addition to the cloud?

Yes. Even with a reliable cloud, keep a physical copy, offline and stored in another location (unplugged drive or tape). It is what saves you when the account closes, when ransomware strikes or when a data centre is destroyed.