This category covers tools for backing up personal and small-office files, synchronising folders between devices and restoring data after loss, theft or ransomware. People use them for photos, documents, device images and archives they cannot afford to lose.
A backup is a complete copy of data that was often never meant to be shared, so the encryption model is the central question. If the provider encrypts on the server and holds the keys, it and any authority that can compel it can read the content. If encryption happens on your device with a key only you hold, the provider stores data it cannot interpret, but a lost key means lost data. The provider's jurisdiction and storage location still matter for availability and metadata. Lock-in appears in proprietary archive formats and in the time needed to download a large backup again when you leave.
When choosing a European option, check whether client-side encryption is documented and who holds the recovery key, whether open or well-documented formats are used, whether you can bring your own storage or self-host, whether versioning is offered, and what is retained after you cancel. The EU Data Act's rules on switching between data-processing services are a useful reference point for portability.