19 rules in 4 groups, worth 100 points in all. They were set before any product was scored and apply the same way to all 10.
Version 1, published 8 Oct 2026
In short
Each rule is a yes-or-no fact, a list (such as the systems with an app) or a number with published thresholds, read from the vendor's own pages.
A fact the vendor does not publish earns nothing. A feature in beta or preview does not count.
The list follows the points. A tie goes to the lower price on "cheapest paid plan with 100 GB or more", then to the name.
Cloud file storage and sync for individuals and families that works on Windows (a sync app or the web). Backup-only services, business-only and enterprise products are left out. A line that says "on at least one plan" counts only plans sold to individuals and families, not team or business plans.
Security and audits 31 points
Rule
What it takes
Points
End-to-end encryption
Record "default" if the vendor documents that all files are encrypted on your device so the vendor cannot read them. Record "option" if this is a separate vault, folder or paid add-on you must switch on. Record "none" if the vendor can read your files. Client-side encryption offered only on business plans counts as "none".
10
Independent security test since 2024
A named outside firm penetration-tested or security-reviewed the apps or the encryption, and the vendor publishes the report or a summary dated 2024 or later. SOC 2 and ISO 27001 reports do not count here; they are scored in the next line.
6
SOC 2 Type II or ISO 27001
The vendor names a SOC 2 Type II report or an ISO/IEC 27001 certification for this product or the company running it.
5
Open-source apps
The source code of the apps is public under an open-source licence.
3
Security key for two-factor sign-in
You can protect the account with a FIDO2 or WebAuthn hardware security key, such as a YubiKey, on at least one plan. Passkeys that live on your phone or computer do not count.
4
Public bug bounty
A public bug bounty programme with published rewards, run by the vendor or on a platform such as HackerOne or Bugcrowd.
3
Apps and sync 20 points
Rule
What it takes
Points
Apps
An official app for each system, not only a web page. Each one earns 2 points.
10
Files on demand in Windows
The Windows app shows all your files in File Explorer and downloads each one only when you open it, or offers a virtual drive that does the same.
6
Choose which folders sync
The Windows app lets you pick which online folders are copied to the PC.
4
Recovery and sharing 22 points
Rule
What it takes
Points
File version and deleted-file history
The longest period, in days, that the service automatically keeps earlier versions of a file or deleted files, on any plan for individuals or families (deleted-file bin time counts). Versions you pin by hand do not count, and limits given as a number of versions instead of days are recorded as null. 365 days or more earns 6 points, 180 days 5, 90 days 4, 30 days 2.
6
Restore the whole account
You can roll all files, or all files in a folder, back to a point in time in one action (ransomware recovery or account rewind), on at least one plan. Restoring files one at a time does not count.
4
Password-protected share links
You can protect a share link with a password, on at least one plan.
4
Edit documents in the browser
The service has its own online editor for documents or spreadsheets, or opens Office files in an editor in the browser, on at least one plan. A plain preview does not count.
4
Plan for five or more people
A plan for individuals that can be shared with at least five people in total, each with their own account or private space.
4
Price and plans 27 points
Rule
What it takes
Points
Free plan with 5 GB or more
A free plan (not a trial) with at least 5 GB of storage. Storage shared with email or photos still counts.
5
Cheapest paid plan with 100 GB or more
Cheapest paid plan with at least 100 GB: yearly price divided by 12 (monthly price if no yearly price is shown), regular price, US dollars before tax; euro prices converted; no US or euro price means null. Bundles count, lifetime plans do not, a shared plan counts in full. $2 or less earns 8, $3 6, $5 4, $8 2.
8
Cheapest paid plan with 1 TB or more
Cheapest paid plan with at least 1 TB: yearly price divided by 12 (monthly price if no yearly price is shown), regular price, US dollars before tax; euro prices converted; no US or euro price means null. Bundles count, lifetime plans do not, a shared plan counts in full. $5 or less earns 8, $7 6, $9 4, $11 2.
8
One-time lifetime plan
The vendor sells a storage plan for individuals with a single payment and no renewal fee, listed on its pricing page. Time-limited sales of it count only if the plan is listed on the regular pricing page.
3
Refund period of 14 days or more
The vendor's pricing page or terms promise a refund (full or prorated) within at least 14 days of buying a paid plan. A refund "at our discretion" does not count.