It depends on your series, and the widely-repeated summary is wrong for two of them. On 2025 DS Plus and desktop FS models an unlisted HDD can create a new storage pool. On the Value and J series it cannot - not for a pool, a cache, or a migration. RS Plus and the enterprise lines allow migration only. Nothing here applies to any Synology launched before 2025. Read from Synology's own tables on 2026-08-19; their last update was 2026-05-27.
Drive compatibility policies FAQs for Synology storage systems starting from 2025 (DSM 7.3 and above), Synology Knowledge Center. Synology's own last-updated stamp: 2026-05-27. We read it: 2026-08-19. Every claim on this page comes from that article, not from reporting about it.
When DSM 7.3 arrived, the story that travelled was that Synology had reversed its 2025 drive restrictions and third-party drives were supported again across the Plus, Value and J series. That is true of one of those three. Synology's own compatibility table shows an HDD that is not on their list as unsupported on the Value and J series - not for a new storage pool, not for cache, not even for migration from another Synology.
This matters because it is exactly the buyer the coverage reaches: someone with a value-tier machine, reading that the policy was reversed, choosing a cheaper third-party drive. On a DS Plus that works. On a J-series box bought in 2025 or later it does not, and they find out when the pool refuses to build.
We are not claiming the reporting was malicious - Synology's announcement emphasised the DiskStation Plus relaxation, and the per-series table is the part that carries the exceptions. But the table is the policy, so the table is what we transcribe.
The column that matters is "Not Listed". If you are choosing a drive on price, or on any recommendation including ours, you are almost certainly in that column - Synology's list is a set of drives they have tested, not a set of drives that work.
| Series | Unlisted HDD | Unlisted 2.5" SATA SSD |
|---|---|---|
| DS Plus series, and desktop FS models DS925+, DS1525+, DS1825+, DS425+ and the rest of the 2025 desktop Plus line | Can create a new storage pool | Can create a new storage pool |
| RS Plus series Rackmount RS Plus models from 2025 | Migration from an existing Synology only | Can create a new storage pool |
| FS, HD, SA, UC, XS+, XS, DP and DVA/NVR series Enterprise and surveillance lines from 2025 | Migration from an existing Synology only | Not supported at all |
| Value and J series DS223, DS224+-class value machines and the J line, 2025 onward | Not supported at all | Not supported at all |
The tables above turn on one column - "Not Listed" - so the obvious next question is which drives are listed. We read the compatibility list itself on 2026-08-19. Every hard drive on it is Synology's own: the HAT5300, HAT5310, HAT5320 and HAS5300, HAS5310, HAS5320 families. There are no third-party hard drives on it at all.
Third-party drives are on the list - 100 of them - and every single one is an enterprise 2.5-inch SSD:
| Third-party entries by type | Rows |
|---|---|
| 2.5" SATA SSD | 88 |
| 2.5" SAS SSD | 12 |
| 3.5" HDD | 0 |
By brand: Samsung 36, Micron 33, Intel 20, Kingston 8, ADATA 1, Apacer 1, MemoRight 1. All of them enterprise class. Source: Synology's compatibility list, read 2026-08-19 with the brand filter set to third-party.
Put the two facts together. On a 2025 or later Value or J-series machine, an unlisted HDD cannot create a storage pool - and no third-party HDD is listed. The practical consequence is that only Synology-branded hard drives can create a storage pool on those machines. On a DS Plus, third-party HDDs work, but every one of them is unlisted by construction, so the Unverified flag and the reduced support scope are not an edge case - they are the normal state of any drive Synology does not make.
Three things make the list hard to read, and any one of them alone produces a confident wrong answer. It is rendered entirely in JavaScript, so an automated fetch returns a shell with no drives in it. It is region-gated: from a non-US address Synology injects a localisation prompt whose dropdown sits over the brand control and swallows clicks on it. And the brand filter defaults to Synology, so the default view shows only Synology drives and looks like a complete list rather than a filtered one.
We mention that because it is our verification trail, not as a criticism of anyone who read it differently. We read the list in a real browser, from a US address, with the brand filter switched to third-party, and we re-check it quarterly. If any of those three conditions had been missed, this page would say something else.
On the flexibility DSM 7.3 introduced:
“with the introduction of DSM 7.3, 2025 DiskStation Plus series models offer more flexibility for installing third-party HDDs and 2.5" SATA SSDs when creating storage pools. While Synology recommends using drives from the compatibility list for optimal performance and reliability, users retain the flexibility to install other drives at their own discretion.”
On whether any of this reaches older machines:
“The new drive compatibility policies apply only to new models starting in 2025 and do not apply retroactively to previously launched systems.”
On what you see when an unlisted drive is permitted:
“The drive is displayed as Unverified in Storage Manager.”
On the condition attached to the migration route:
“Drives must be migrated directly from an existing Synology system. If the original storage pool or SSD cache is removed from the drive, the drive will no longer be usable in your current Synology system.”
Find your series first, because it decides everything else. If your machine predates 2025, stop reading - none of this applies to you and any drive that physically fits and meets the interface will work as it always did.
If you have a 2025-or-later DS Plus or desktop FS, you have a genuine choice. An unlisted drive will create a pool and will be flagged as Unverified in Storage Manager. That flag is a label rather than a restriction on those models, and the trade you are making is Synology's testing for whatever the price difference is - which at current prices is frequently substantial.
If you have a 2025-or-later Value or J-series machine, the choice is narrower than the internet will tell you. Check Synology's compatibility list for your exact model before you buy anything, because on that series an unlisted HDD is not a warning, it is a wall.
And on the enterprise and RS Plus lines, the migration-only route is real but conditional: the pool has to travel intact on the drive. That makes it a path for moving an existing array, not a way to buy cheaper drives for a new one.
Synology's article shows when they last updated it. We show when we last read it. Those are different facts and both matter: a vendor page can sit unchanged for months while nothing about the policy is settled, and a page like ours can go stale while the vendor moves. Neither date alone tells you whether to trust this.
This policy has changed before. It changed during 2025 and again with DSM 7.3, and the reporting has lagged it each time. We treat it as a volatile claim with a scheduled re-check rather than as a fact we can write once - the next verification is due by 19 November 2026. If you are reading this after that date and it has not been re-dated, go to Synology.
NAS devices compared · What it costs to fill a NAS · NAS drives by price per TB · CMR/SMR list · Today's best NAS drive
It depends entirely on which series you own, and this is where most coverage of the story goes wrong. On 2025 DS Plus and desktop FS models, an HDD that is not on Synology's compatibility list is supported for a new installation and for creating a storage pool - that is the relaxation DSM 7.3 introduced. On the 2025 Value and J series it is not: Synology's table shows an unlisted HDD as unsupported for a new pool, for cache, and for migration. RS Plus and the enterprise lines sit in between, at migration-only. We quote the table below and date it, because it has changed before.
No, if it was launched before 2025. Synology states it directly: "The new drive compatibility policies apply only to new models starting in 2025 and do not apply retroactively to previously launched systems." That is one of the few completely unambiguous sentences in this area, and it means an older DS920+ or DS1621+ is not subject to any of the tables on this page.
On the series where it is permitted, the drive works and Synology marks it. Their words: "The drive is displayed as Unverified in Storage Manager." On the series where it is not permitted, the operation the table denies is genuinely unavailable - you do not get a warning you can dismiss, you get a drive you cannot build the pool you wanted with. Which of those two situations you are in is decided by your model's series, not by the drive.
Synology gives two reasons for the RS Plus split. One is availability: their list carries a broad range of NAS and enterprise HDDs, but only enterprise-grade 2.5-inch SATA SSDs, so restricting SSDs to the list would leave buyers with very few options. The other is impact - they argue the mechanical nature of HDDs affects overall system performance and reliability more. For M.2 NVMe the reasoning is different again and is about cache workloads: "To ensure system reliability, only M.2 NVMe SSDs meeting strict performance, endurance, and thermal management requirements are supported for creating storage pools and caches."
On several series that is the only route an unlisted drive has, and it carries a condition worth reading twice: "Drives must be migrated directly from an existing Synology system. If the original storage pool or SSD cache is removed from the drive, the drive will no longer be usable in your current Synology system." In other words the migration path depends on the pool staying intact on the drive. Wipe it and you are back to the new-installation rule, which on those series is a refusal.
Only Synology's own. We read the list on 2026-08-19: every HDD on it belongs to the HAT5300, HAT5310, HAT5320, HAS5300, HAS5310 or HAS5320 families. There are 100 third-party entries and all of them are enterprise 2.5-inch SSDs - 88 SATA and 12 SAS, from Samsung, Micron, Intel, Kingston, ADATA, Apacer and MemoRight. Zero third-party 3.5-inch hard drives. That is why the "Not Listed" column in the tables above is the one that matters for anyone buying an HDD: whatever drive you choose, unless it is a Synology one, it sits in that column.
We read Synology's article on 2026-08-19; their own last-updated stamp on it was 2026-05-27. Both dates are on this page because they are different facts - theirs tells you when the policy last moved, ours tells you when we last checked. This policy has changed before, so we re-verify it quarterly and the next check is due by 2026-11-19. If you are reading this well past that date and nothing has been re-dated, treat it as stale and go to the source.