Will this fit · Reviewed October 14, 2026 · Prices updated 1 hour ago

Why Is My NAS Not Detecting My Hard Drive?

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Back up before you repair. If the data on this system exists nowhere else, copy what matters to another device first, while the drives still read.

Quick answer

Start with the checks that cost nothing: reseat the drive, try it in an empty slot, and on Synology update the drive database. A SAS drive will not work on a SATA controller, so in a SATA-only NAS the fix is a SATA drive. If the missing drive was part of a storage pool, check the pool's status before you move anything.

Reviewed October 14, 2026

Check your situation

What does the NAS show for the drive?

On Synology, look in Storage Manager > HDD/SSD. On QNAP, look in Storage & Snapshots.

Reseat the Drive and Try Another Slot. UGREEN says to make sure the drive slot is secure and not loose, then reseat the drive and see whether the status improves. On rack-mount Synology models, tighten the screws that hold the drive in its tray. QNAP's step for a new disk that is not detected: remove it, restart the NAS, insert it again, then check that Storage & Snapshots shows it. The NAS beeps twice when a disk goes into a bay. If the drive sits in a Synology expansion unit, check the unit is compatible with your model and the expansion cable is securely connected. Synology says to try the drive in an empty slot if you have one. If you have none, connect it to a computer to see if it works. Nothing needs buying for these checks. If the drive still does not show, come back to the slot question with what you found.

The Slot Is at Fault, Not the Drive. If the drive is identified in a different slot, Synology says the problem likely lies with the previous slot. In a swap test, if a healthy drive then shows errors in that slot, the slot is likely faulty. Synology disables a drive slot when the system fails to connect to the drive more than three times. If your device is within warranty, Synology says to contact your local reseller or distributor for an RMA. For a faulty slot, Synology recommends backing up all your data and replacing the Synology storage system. No drive needs buying: the drive works.

Update the Drive Database Before Anything Else. Synology's statuses mean different things. Unrecognized means the system cannot recognize or use the drive. Incompatible means it tested incompatible. Unverified means it has not been verified as compatible. Synology's first step for all three is to bring the drive database up to date. The database holds the compatibility list. If the status stays, check the Synology Products Compatibility List for your model. Synology says drives not on it might not function properly. UGREEN asks you to check its compatibility list or user manual, and says incompatible disks may stop the NAS working correctly. Nothing needs buying if the database update clears the status.

The NAS Will Not Start With the Drive In. Synology checks the system partition on each drive at startup and stops if it finds an abnormality. Identify the problem drives and power on with the rest. Synology's drive-by-drive test puts one drive in the Drive 1 slot and powers on. The Power LED should turn static blue or green within 10 minutes. UGREEN says that if a drive error causes a power-on self-test failure, power off, remove the suspect drive and restart. With the problem drives left out, Synology says the storage pool should be Degraded, and new drives go in to repair it. The degraded pool page covers that repair. Nothing needs buying until the test shows which drive is at fault.

Shucked Drive: Read the 3.3V Pin Page. The site's 3.3V pin page covers a shucked drive that powers up in its external enclosure but not in a NAS or PC. This page does not restate that fix. Read the pin page before you buy anything.

SAS Drive in a SATA Bay: It Will Not Work. Seagate says SATA drives can go on SAS controllers, but SAS drives cannot be plugged into SATA controllers. Connecting a SAS drive to a SATA controller will not work. The Drive Interface Checker on this page gives a will-not-work verdict for a SAS drive in any NAS it lists, because their bays are recorded as SATA. Nothing you can buy makes the drive work in that NAS. For UGREEN models, the checker adds that UGREEN's compatibility page says SAS drives are not supported. The fix is the SATA version of the drive. The SATA drives in the table below fit that role. If you want to use the SAS drive in a PC instead, the checker prices an HBA and cable for that.

The Drive Itself Is Likely Faulty. If Synology Assistant shows Not installed after you move the drive to other slots, Synology says the drive itself may be faulty and to try a different drive. In a swap test, if the suspect drive still shows errors in its new slot, Synology says the drive is likely faulty. Check the replacement against the Synology Products Compatibility List for your model. If the failed drive caused a disabled slot, put the healthy replacement in, then in Storage Manager > HDD/SSD select the drive marked Drive slot disabled and click Enable Drive Slot.

Work it out for your hardware

The drive isWhere it is going

The model lookup covers 339 model numbers whose maker data sheet states the interface: Seagate Exos, IronWolf, IronWolf Pro and BarraCuda, WD Gold and Ultrastar, and Toshiba MG. For any other drive, read SAS or SATA from its label.

Needs an HBA and a cable

SAS drive, PC with onboard SATA: needs an HBA and a cable

Connecting a SAS drive to a SATA controller will not work, so the motherboard's SATA ports are out. A SAS host bus adapter in a free PCIe slot runs the drive, with a breakout cable that ends in SFF-8482 plugs, the connector on a SAS drive.

Full cost today: $69.67 for one card and one cable, which connects up to four SAS drives.

LSI 9207-8i family

KCMconmey LSI 9207-8i Controller HBA Card, LSI 2308 SATA SAS Host Bus Adapter. 2 * SFF-8087 Internal 6Gbps, PCI-e 3.0 x8. IT Mode Firmware. Non RAID.

What this listing states: Listed as new; the listing states SFF-8087 connectors, 6Gb/s; it states IT or HBA mode firmware.

$54.99Buy on Amazon

SFF-8087 to 4 SFF-8482 SAS breakout cable

ADCAUDX Mini-SAS to SAS-Cable: 1M SFF8087 to SAS SFF-8087 to SFF-8482

What this listing states: SFF-8087 on the card side to SFF-8482 SAS drive connectors (as the listing describes it); the listing does not mention power connectors, so check how each drive gets power.

$14.68Buy on Amazon

If the drive is not bought yet, a SATA drive of the same size needs none of this.

The rules this tool applies, with their sources, are on its own page: Drive Interface Checker.

Safe steps

These actions can lose data. Do none of them until a copy exists elsewhere:

A pool drive that went missing can leave the pool degraded, or crashed. For an accidentally removed drive, Synology says to reinsert that same drive and repair the pool it belonged to; for a crashed pool on DSM 7, reinsert it and perform an online assemble from Storage Manager > Storage.
Synology says to make sure every storage pool, dual pool and volume is Healthy before a swap test that moves drives between slots.
Synology says a drive showing Incompatible, Unverified or Unrecognized is not on its compatibility list, and using it could affect system stability and result in data loss.
Synology says all drives in a storage pool must be the same type. SATA, SAS and NVMe drives cannot be mixed.

If your model does not support hot swapping, shut it down before you switch drive slots. The model's datasheet says whether it does.^[1]
QNAP says to power off before removing a disk on a NAS without hot-swapping.^[7]
UGREEN says to power off the NAS and unplug the power cable before installing a hard disk.^[9]
After each change, check whether the drive appears in Storage Manager > HDD/SSD.^[1]

What to buy, if anything

Answer the questions under "Check your situation" and this section narrows to what your case calls for. Until then every table is shown, each with the case it is for.

SATA NAS drives to replace a dead or SAS drive

Why this is here: Shown only for two outcomes: the drive itself is faulty (it is not found in any slot or on a computer), or it is a SAS drive in a SATA-only NAS, where the fix is a SATA drive. A bay, seating, power or database problem needs no purchase. New 3.5-inch SATA NAS and enterprise hard drives whose maker confirms CMR recording, with today's Amazon.com price per TB.

Price per

Sort

30 products

Product	Capacity	Price	$ / TB	Type	Prime	Buy
DC HC550 16TB 512MB SATA Ultra SE NP3	16 TB	$589.45	$36.84	Enterprise HDD · SATACMREnterprise	-	Buy on Amazon
Seagate IronWolf 14TB NAS Internal Hard Drive HDD – CMR 3.5 Inch SATA 256MB Cache for RAID Network Attached Storage – Frustration Free Packaging (ST14000VN0008)	14 TB	$525.00	$37.50	NAS HDD · SATACMR	-	Buy on Amazon
TOSHIBA N300 Internal Hard Drive 22 Tb 7200 RPM 512 Mb 3.5", W129161818 (Tb 7200 RPM 512 Mb 3.5 Serial Ata Iii)	22 TB	$830.82	$37.76	NAS HDD · SATACMR	-	Buy on Amazon
Toshiba - HDWG82AXZSTB - Toshiba N300 Pro HDWG82AXZSTB 20 TB Hard Drive - 3.5 Internal - SATA (SATA/600) - Conventional	20 TB	$766.99	$38.35	NAS HDD · SATACMR	-	Buy on Amazon
Toshiba MG Series Enterprise 12TB 3.5’’ SATA 6Gbit/s Internal HDD 7200RPM 550TB/year 24/7 Operation. MG07ACA12TE	12 TB	$469.99	$39.17	Enterprise HDD · SATACMREnterprise	-	Buy on Amazon
Seagate IronWolf Pro, 16 TB, Enterprise NAS Internal HDD –CMR 3.5 Inch, SATA 6 Gb/s, 7,200 RPM, 256 MB Cache for RAID Network Attached Storage (ST16000NT001)	16 TB	$629.99	$39.37	NAS HDD · SATACMR	-	Buy on Amazon
Seagate Enterprise 3.5" 18000 GB 7200 RPM 18 TB 3.5" 7200 RPM SATA ST18000NM00J	18 TB	$712.00	$39.56	Enterprise HDD · SATACMREnterprise	-	Buy on Amazon
Seagate Enterprise Capacity \| ST10000NM0016 \| 10TB 7200 RPM SATA 6.0Gb/s 256MB Cache Hyperscale 512e 3.5" Hard Disk Drives	10 TB	$399.95	$39.99	Enterprise HDD · SATACMREnterprise	-	Buy on Amazon
Western Digital WUH721414ALE6L4 14TB Ultrastar DC HC530 SATA HDD - 7200 RPM Class, SATA 6 Gb/s, 512MB Cache, 3.5"	14 TB	$581.00	$41.50	Enterprise HDD · SATACMREnterprise	-	Buy on Amazon
Seagate 20TB Exos Enterprise Hard Drive \| SATA (ST20000NM002H) \| Enterprise nearline HDD for AI, cloud & data centers. Always-on performance, helium sealed, 2.5M-hr MTBF. 5-Year Warranty	20 TB	$829.99	$41.50	Enterprise HDD · SATACMREnterprise	-	Buy on Amazon
Toshiba - HDWG81GXZSTB - Toshiba N300 Pro HDWG81GXZSTB 16 TB Hard Drive - 3.5 Internal - SATA (SATA/600) - Conventional	16 TB	$685.50	$42.84	NAS HDD · SATACMR	-	Buy on Amazon
Seagate 14TB HDD Exos X14 7200 RPM 512e/4Kn SATA 6Gb/s 256MB Cache 3.5-Inch Enterprise Hard Drive (ST14000NM0018)	14 TB	$600.00	$42.86	Enterprise HDD · SATACMREnterprise	-	Buy on Amazon
HGST WD Ultrastar DC HC510 10TB 7200 RPM SATA 6Gb/s 3.5" Helium Platform Enterprise Hard Disk Drive - HUH721010ALE604 (0F27606)	10 TB	$429.00	$42.90	Enterprise HDD · SATACMREnterprise	-	Buy on Amazon
Seagate Exos X18 Enterprise Class, 16TB, Enterprise Internal Hard Drive, SATA, 3,5" 6Gbit/s, 128MB Cache (ST16000NM000J)	16 TB	$686.91	$42.93	Enterprise HDD · SATACMREnterprise	-	Buy on Amazon
Seagate IronWolf 10TB NAS Internal Hard Drive, 3.5" SATA 6Gb/s, 7200 RPM, CMR, RAID Optimized, IronWolf Health Management – for NAS Systems (ST10000VNZ00)	10 TB	$432.99	$43.30	NAS HDD · SATACMR	-	Buy on Amazon
Western Digital 22TB WD Red Pro NAS Internal Hard Drive HDD - 7200 RPM, SATA 6 Gb/s, CMR, 512 MB Cache, 3.5" - WD221KFGXSold by Amazon	22 TB	$958.90	$43.59	NAS HDD · SATACMR	Prime	Buy on Amazon
Seagate Exos X10 ST10000NM0126 10TB 7200 RPM SATA 6Gb/s 512e 256MB 3.5in Enterprise Hard Drive	10 TB	$439.99	$44.00	Enterprise HDD · SATACMREnterprise	-	Buy on Amazon
Western Digital 20TB WD Red Pro NAS Internal Hard Drive HDD - 7200 RPM, SATA 6 Gb/s, CMR, 512 MB Cache, 3.5" - WD202KFGXSold by Amazon	20 TB	$881.68	$44.08	NAS HDD · SATACMR	Prime	Buy on Amazon
Western Digital 18TB WD Red Pro NAS Internal Hard Drive HDD - 7200 RPM, SATA 6 Gb/s, CMR, 512 MB Cache, 3.5" - WD181KFGX	18 TB	$794.99	$44.17	NAS HDD · SATACMR	-	Buy on Amazon
Western Digital 24TB WD Red Pro NAS Internal Hard Drive HDD, 7200 RPM, SATA 6 Gb/s, CMR, 512 MB Cache, 3.5" - WD241KFGXSold by Amazon	24 TB	$1,059.99	$44.17	NAS HDD · SATACMR	Prime	Buy on Amazon
Seagate IronWolf Pro 14TB NAS Internal Hard Drive HDD – CMR 3.5 Inch SATA 6Gb/s 256MB Cache for RAID Network Attached Storage, Data Recovery Service – Frustration Free Packaging (ST14000NEZ008)	14 TB	$619.99	$44.29	NAS HDD · SATACMR	-	Buy on Amazon
Seagate IronWolf 16TB NAS Internal Hard Drive HDD – CMR 3.5 Inch SATA 6GB/S 7200 RPM 256MB Cache for Raid Network Attached Storage, with Rescue Service (ST16000VN001)	16 TB	$711.00	$44.44	NAS HDD · SATACMR	-	Buy on Amazon
Seagate IronWolf Pro ST12000NE0008 12 TB Hard Drive - 512E Format - SATA 600-3.5" Drive - Internal - 7200RPM - 256 MB Buffer - Hot Pluggable	12 TB	$534.99	$44.58	NAS HDD · SATACMR	-	Buy on Amazon
Seagate Exos X14 ST12000NM0008 12 TB Hard Drive - 3.5" Internal - SATA (SATA/600)	12 TB	$535.68	$44.64	Enterprise HDD · SATACMREnterprise	-	Buy on Amazon
Western Digital 16TB WD Red Pro NAS Internal Hard Drive HDD - 7200 RPM, SATA 6 Gb/s, CMR, 512 MB Cache, 3.5" - WD161KFGXSold by Amazon	16 TB	$714.99	$44.69	NAS HDD · SATACMR	Prime	Buy on Amazon
Western Digital 12TB WD Red Plus NAS Internal Hard Drive HDD - 7200 RPM, SATA 6 GB/s, CMR, 512 MB Cache, 3.5" - WD120EFGX	12 TB	$538.88	$44.91	NAS HDD · SATACMR	-	Buy on Amazon
Western Digital 12TB WD Red Pro NAS Internal Hard Drive HDD - 7200 RPM, SATA 6 Gb/s, CMR, 512 MB Cache, 3.5" - WD122KFBXSold by Amazon	12 TB	$539.16	$44.93	NAS HDD · SATACMR	Prime	Buy on Amazon
Seagate IronWolf 10Tb NAS Internal Hard Drive HDD – 3.5 Inch SATA 6GB/S 7200 RPM 256MB Cache for Raid Network Attached Storage (ST10000VN0004)	10 TB	$449.99	$45.00	NAS HDD · SATACMR	-	Buy on Amazon
HGST - WD Ultrastar DC HC520 HDD \| HUH721212ALE600 \| 12TB 7.2K SATA 6Gb/s 256MB Cache 3.5-Inch Helium Data Center Internal Hard Disk Drive	12 TB	$541.45	$45.12	Enterprise HDD · SATACMREnterprise	-	Buy on Amazon
Western Digital 10TB WD Red Plus NAS Internal Hard Drive HDD - 7200 RPM, SATA 6 GB/s, CMR, 512 MB Cache, 3.5" - WD100EFGXSold by Amazon	10 TB	$455.75	$45.58	NAS HDD · SATACMR	Prime	Buy on Amazon

Sources

Synology knowledge center: What should I do if the installed drives do not appear in Storage Manager? checked 2026-10-14
Synology knowledge center: Drive errors occurred, but I am not sure if they resulted from the drives or the drive slots. How do I check? checked 2026-10-14
Synology knowledge center: What should I do if my drive slots are disabled? checked 2026-10-14
Synology knowledge center: Storage Manager shows my drive as "Incompatible", "Unverified", or "Unrecognized". What can I do? checked 2026-10-14
Synology knowledge center: My Synology NAS cannot enter "Ready" status after installing drives. What can I do? checked 2026-10-14
Synology knowledge center: How do I repair a storage pool or dual pool if a drive was accidentally removed? checked 2026-10-14
QNAP FAQ: How do I replace a faulty disk in a RAID group? checked 2026-10-14
UGREEN knowledge center: How to Determine the Status and Identify Errors of UGREEN NAS via LED Indicators? checked 2026-10-14
UGREEN knowledge center: Hard Disk Installation Assistant (Hardware Disassembly and Risk Notification) checked 2026-10-14
Seagate knowledge base: Connecting SATA drive to SAS controller checked 2026-10-14
Seagate knowledge base: Serial-Attached SCSI Installation Instructions checked 2026-10-14

Facts on this page were reviewed on October 14, 2026. Prices and stock are from Amazon.com as of October 14, 2026.