Ransomware has become the #1 cause of data loss in France. One phishing email, one opened attachment, and all your files get encrypted — unreadable without paying a ransom (usually in bitcoin).
In Cluses, I regularly come across home users and SMEs who suddenly lose photos, accounting documents, client invoices. The good news: 95% of attacks could have been avoided with basic precautions.
1. Back up with the 3-2-1 rule
A real backup follows the 3-2-1 rule:
- 3 copies of your files
- On 2 different media (internal + external drive)
- Including 1 off-site (encrypted cloud, or disk at a friend's house)
2. Update Windows / macOS
Ransomware exploits flaws already patched by Microsoft / Apple. Skipping updates leaves the door open.
3. An effective antivirus (not Avast)
Free antivirus like Avast, AVG or McAfee slow down your PC without protecting well. To my Arve Valley clients I recommend:
- Microsoft Defender (free, built into Windows 11)
- Bitdefender Total Security (€35/year, best in 2026)
- ESET NOD32 (€40/year, lightweight and precise)
4. Never click on suspicious attachments
80% of ransomware arrives by email. Watch out for:
- Fake Chronopost, La Poste, DHL ("your parcel could not be delivered")
- Fake French tax authority emails ("refund available")
- Fake Microsoft / Apple emails ("your account is about to expire")
- Attachments in .zip, .rar, .exe, .scr, .js you didn't expect
5. Limit admin privileges
Create two accounts on your personal PC:
- An admin account (to install software)
- A standard user account for daily use
What to do if infected
Never pay the ransom. Call a professional — in Cluses, I offer an €80 diagnostic flat rate to assess recovery chances.
Need a security audit? Call +33 7 83 44 65 99 — free first diagnosis, on-site in Cluses, Sallanches, Bonneville and the whole Arve Valley.