Synology's 2025 Drive Policy Explained: DSM 7.3, Third-Party Drives and Your Compatibility List
Compatibility data on this site last refreshed 2026-11-03 · reading time ~3 min
In 2025 Synology changed its hard-drive policy twice, in opposite directions, and most of the advice you will find online is now out of date for one half of the story or the other. This page lays out the whole timeline, which models are affected by which rule, and what it means when a drive is not on your machine's official compatibility list.
The timeline: restrict, backlash, walk back
April 2025: Synology launched its 2025-model Plus series (DS925+, DS1525+, DS1825+, DS725+ and others) with a policy that only Synology-branded and Synology-verified drives — the HAT5300/HAT3300 enterprise range and a small set of verified models — could be used to create new storage pools. Existing drives kept working, but you could not build a new pool with a retail WD Red Pro or Seagate IronWolf. The community reaction was immediate and overwhelmingly negative, and it made headlines well beyond the NAS hobbyist press.
October 8, 2025: Synology shipped DSM 7.3 with what it calls the HCL 5.0 framework. For 2025-model DiskStation Plus, Value and J series, the restriction was lifted: drives that are not on the compatibility list — but also not on the new incompatibility list — are once again fully supported for installation, storage-pool creation and volume management, with no warnings and no feature loss.
Which models are affected by which rule
- 2025 DiskStation Plus, Value and J series (DS925+, DS1525+, DS1825+, DS425+, DS225+, DS725+ etc.): third-party HDDs and 2.5-inch SATA SSDs work for pool creation even when unlisted. Only drives explicitly on the incompatibility list are blocked.
- Rackmount Plus (RS series), DVA/NVR surveillance units: stricter policy retained. Unlisted HDDs are accepted for migration from an existing Synology system, but cannot be used to create new storage pools or caches.
- Enterprise lines (FS, HD, SA, UC, XS, XS+): unlisted drives are migration-only. New pools and caches require listed drives.
- M.2 NVMe SSDs on every 2025 line: still restricted. New NVMe pools and cache volumes require drives from the official compatibility list, on the reasoning that NVMe caching runs hotter sustained loads.
- Every model launched before 2025: the new policy does not apply retroactively. These machines were never restricted in the first place and continue to accept any compatible drive.
The three-tier system: listed, unlisted, incompatible
DSM 7.3 also formalised a vocabulary that matters when you read any compatibility list, including the per-model lists on this site. Listed drives are fully supported for everything. Unlisted drives (not on either list) range from fully supported on 2025 desktop models to migration-only on enterprise gear. Incompatible drives are blocked outright — Synology uses this list for drives that fail its thermal or firmware testing.
The practical catch is support, not function: on unlisted drives, the NAS itself runs normally with full S.M.A.R.T. monitoring, but Synology's technical support may decline assistance for problems traced back to the unlisted drive. That is the trade you are making.
How to check whether your model accepts unlisted drives
- Find your exact model on its page on this site — the per-machine list shows what the vendor officially lists today.
- If your model is a 2025 or later Synology Plus/Value/J series: unlisted HDDs and SATA SSDs work for new pools on DSM 7.3 or newer.
- If it is pre-2025 Synology: nothing changed; any drive that meets the interface works, and the compatibility list is advisory.
- If it is Synology RS/DVA/NVR/enterprise: assume unlisted drives are migration-only and budget for listed drives on new builds.
- If it is QNAP, Asustor or TerraMaster: none of these policies apply. All three vendors publish advisory compatibility lists only — unlisted drives work, you just fall outside the tested matrix.
What this means when you use the lists on this site
Every machine page here shows the vendor's official list, refreshed daily. An entry on that list is a statement that the vendor has tested the drive in that machine — it is the strongest signal you can get. Absence from the list now means different things depending on the row above: on most machines it is still a soft signal, and for a growing set of models the vendors themselves say unlisted is fine. Buy from the list when you want zero doubt; buy off-list only when you understand your model's policy tier.
Quick answers
Does the 2025 Synology drive restriction apply to my older DS923+?
No. The April 2025 policy only affects models released in 2025 or later. A DS923+ or any pre-2025 machine accepts any compatible drive exactly as before.
Can a DS925+ use a WD Red Pro or Seagate IronWolf now?
Yes. Under DSM 7.3's HCL 5.0 framework, 2025 Plus/Value/J series accept third-party HDDs and 2.5-inch SATA SSDs for storage pools even when unlisted — only drives on the incompatibility list are blocked.
Are unlisted M.2 NVMe SSDs allowed for caching?
No. NVMe caching and NVMe storage pools still require drives from the official compatibility list on every 2025-model line.
What happens if a drive is on the incompatibility list?
It is blocked outright: no installation, no pool creation. Synology places drives that fail its thermal or firmware testing on this list.
Check your exact model
Compatibility is per machine and per part number. Pick your model for its full official drive list: