The answer — one pick, priced
Get the
WD My Book 18TB
no budget ceiling
The archive nobody else can read — 256-bit AES and password protection across 18TB at about $32/TB, within $2/TB of the unencrypted Seagate.
Fit ledger — need → measured evidence
■ The catch — co-equal billing, always
You pay $86 more for a slower drive. It runs about 200 MB/s against close to 280 MB/s on the Seagate Expansion Desktop, still needs a wall outlet and USB-A — and its $570 is a 24% discount off a $754.99 list in a market that has risen 46% since September 2025, so the discount can evaporate.
Dealbreaker? Runner-up №1 (Expansion 16TB) is faster and $86 cheaper, without encryption ↓
■ Every product has a catch. Verdicts that hide it are how bad buys happen.
Don't buy this if…
- you need maximum transfer speed or durability for travel (not capacity)external ssds dossier →
- you need internal NAS drives for a network storage enclosurenas hard drives dossier →
- you need under 4TB, values speed over capacity, and can absorb 2026 flash pricing (~$110-150/TB for a portable SSD)external ssds dossier →
Wrong product for you is still a bad buy. These are the cases where we'd send you somewhere else.
Runners-up — if your needs differ
Adjacent verdicts — other needs, same method
Different budget, different household, different job — each of these is already researched, priced and verified. Take the one that matches your need.
Traps — this verdict avoids
Why the WD My Book 18TB is right for you
It avoids every trap below — and for just me, no budget cap, it is the pick because it delivers:
Capacity is the SKU
Cost per terabyte is steeply non-linear, and bigger is often cheaper: the 12TB WD Elements Desktop costs $530 while the 16TB Seagate Expansion costs $484 for 4TB more. Compare $/TB, never the sticker price.
The 28TB that vanished
Seagate's Expansion 28TB — the old $/TB champion at ~$290 — is sold out at Amazon, Best Buy, Walmart and Newegg with no backorder date, and third-party sellers now ask ~$1,000. Refurbished batches are circulating too.
The USB-C that isn't
Most portable HDDs still ship a Micro-B connector, not USB-C. WD's My Passport "Works with USB-C" has no USB-C port on the drive — it bundles an adapter. On a USB-C-only laptop you are buying a dongle either way.
Provenance — 12 sources, dated
Winners are picked from the full research dossier at knowledgelib.io. Prices, stock and listings are re-verified monthly.