Can data be recovered from a RAID or NAS?
Short answer
Usually yes, and the outcome depends on which failure you had. One dead drive in a redundant array leaves the data on the surviving drives, and vendor manuals document the rebuild. A second failure during a rebuild, a dead controller, or re-creating the array are the cases that end up at a lab, and both NAS makers and recovery labs say the same first move: power down and leave the members alone.
Usually, yes. The odds turn on which failure you had, not how big the NAS is. One failed drive in a redundant array leaves the data intact on the surviving drives: QNAP documents recovering an inactive RAID 1, 5, 6, 10, 50 or 60 volume from degraded mode, with a table capping RAID 5 at one removed drive and RAID 6 at two. The dangerous cases are a second drive failing during a rebuild, a dead controller, and anything that re-creates or re-initializes the array. Those end up at a lab, and both NAS makers and labs give the same first instruction: shut the system down and leave the members alone.[1][2][3]
One drive down in a redundant array
This is the case NAS makers design for. QNAP's steps for a failed RAID 5 member are to 'Prepare a new hard drive with a capacity that is the same as or larger than the failed hard drive', install it, and verify the volume status shows Rebuilding. Western Digital's EX2 Ultra manual adds one instruction for the hours that follow: 'Do not attempt to use the device during the rebuild process.'[3][4]
A degraded array keeps serving files, but it is running with no fault margin left. Western Digital gives the EX2 Ultra a flashing red 'Power Up (degraded)' LED for when the volume is degraded, and QNAP's beeper table lists degraded drives and a rebuilding drive as alert conditions. Until the rebuild finishes, one more failure loses the volume.[4][3]
The dangerous cases
The second failure is what turns a routine swap into a recovery job. A degraded array has no spare parity to cover another drive, and SalvageData lists 'RAID rebuild failed or was interrupted' among the cases it triages. Re-initialization is the self-inflicted version: Western Digital warns that 'Changes made to your RAID Mode will delete all of your data and your user settings', and QNAP warns that 'Installing QTS deletes all data on the drives'. Rebuilding in place is what vendors document; re-creating the volume to fix a problem is what destroys it.[1][4][3]
A dead controller, or a NAS that will not start its volume at all, is the other route to a lab. Secure Data Recovery lists multiple drive or SSD failures, damaged controllers, failed rebuilds and parity errors among the scenarios it works, and describes recreating the RAID parameters and drive order, deducing the array's structures by hand when the RAID metadata is gone. The lab is describing its own capabilities, but the case is a known one.[2]
Stop and get advice before touching the array if a rebuild has already failed, if the NAS asks you to re-create or re-initialize the volume, or if you are not sure which drive failed. Never re-create or re-initialize the array to fix it: WD warns that changes to RAID mode delete all data and user settings, and QNAP warns that installing QTS deletes all data on the drives. Never force repeated rebuilds, and do not reset the system, remove and reinsert members, run CHKDSK or fsck, or put free recovery software on the array: Secure Data Recovery's do-not list names each of those, and SalvageData warns that repairing a RAID without proper tools can lead to permanent data loss. Shut the system down as soon as you notice a problem, and label the drive order before anything else happens.[2][1][4][3]
What a lab does with a failed array
Sending a NAS in does not mean giving up the hardware: SalvageData states NAS data recovery can be done on-site or remotely, and Secure Data Recovery describes diagnosing the issue inside a certified cleanroom and developing a plan to recover data. The reconstruct-the-array work above is exactly what you are paying for.[1]
When the array is fine but the files are gone
Sometimes the hardware is healthy and the loss happened on top of it: a share deleted by accident, a file table encrypted or wiped, ransomware that reached the NAS over the network. Secure Data Recovery says its specialists can often recover data even when the file table is encrypted or deleted, and SalvageData lists ransomware and malware among the RAID and NAS cases it triages. Those are different problems, so follow the guidance for deleted files or ransomware, not a rebuild.[1][2]
Related reading
RAID 5 failure: rebuild mistakes that lose data
How to choose a data recovery service
What does data recovery cost in the US?
Guided help: find the right path for your situation
Sources
Facts on this page are cited to the publishers’ own documentation.
- [1] SalvageData — RAID Data Recovery Services | SalvageData. captured 2026-09-13.
- [2] Secure Data Recovery — Professional RAID Data Recovery Services. captured 2026-09-13.
- [3] QNAP — QNAP TS-364 user guide. captured 2026-09-12.
- [4] Western Digital — My Cloud EX2 Ultra user manual. captured 2026-09-12.