do HDD and SSD data recovery techniques differ.
September 24, 2025
When data goes missing, the right recovery plan depends on the type of drive. Hard disk drives (HDDs) store data magnetically on spinning platters; solid-state drives (SSDs) store data in flash memory managed by a controller. Those differences change how data fails, how labs recover it, how long it takes, and what you should do next.
key takeaways.
HDDs often fail mechanically or from media damage; recovery may require cleanroom work (head swaps, firmware repairs) before imaging.
SSDs fail logically, electrically, or at the controller/firmware level; recovery may involve low-level access to the controller, JTAG, or chip-off techniques to read raw NAND.
TRIM and wear-leveling on SSDs can permanently erase deleted data; rapid power-down and avoiding writes are critical.
The safest first step for both: stop using the device and seek a professional evaluation – most reputable labs offer a free diagnostic to confirm whether recovery is possible before any fees apply.
quick comparison.
Hard disk drives (HDDs) store data on spinning magnetic platters that are read by tiny heads mounted on an actuator arm, while solid‑state drives (SSDs) keep information inside NAND flash chips managed by a controller and its flash‑translation layer (FTL). Because HDDs are electromechanical, they most often fail when the read/write heads crash onto the platters, the spindle motor seizes, platters become scratched, sectors turn bad, or firmware modules go corrupt. SSDs, by contrast, usually stumble electronically: the controller or its firmware fails, NAND cells wear out, power surges burn components, or the TRIM command logically erases data.
For that reason, HDD recovery starts in a Class 100 (ISO 5) cleanroom where technicians swap heads or perform other delicate mechanical repairs, patch firmware, and then image the disk sector by sector. SSD recovery is mostly logical and electronic: labs talk directly to the controller, use JTAG fixtures or vendor utilities, repair firmware, and - if necessary - desolder the NAND chips (“chip‑off”) to read them and reconstruct the FTL offline.
Missteps that worsen damage also differ. A clicking HDD becomes harder to save if it’s repeatedly powered up, subjected to DIY software that writes to it, or opened outside a cleanroom. An SSD is endangered when it’s written to after data loss (because TRIM and garbage collection can wipe remnants), power‑cycled on a flaky controller, or exposed to high heat. Overall complexity skews mechanical for HDDs and vendor‑specific electronic for SSDs. Finally, encryption is only occasionally an obstacle on HDDs but is common on modern SSDs, so a valid password or key is critical for success.
how the technology shapes recovery.
HDDs: Mechanical systems first, data second
HDDs rely on precise mechanics. All mechanical work is performed inside a Class 100 cleanroom (fewer than 100 airborne particles per cubic foot) to match original factory assembly conditions. If heads can’t read, the lab may replace them with matched donor parts, stabilize firmware, then capture a forensic image that skips weak areas and revisits them later. Once a stable clone exists, file system repair and carving are performed off the original media.
SSDs: Flash memory managed by a controller
SSDs map logical file locations to constantly moving physical pages through a Flash Translation Layer (FTL). Features like wear‑leveling, garbage collection, and TRIM boost performance but complicate recovery.
Labs may:
- JTAG - attach to test‑access pads to interrogate the controller without lifting chips.
- Controller/firmware repair - restore normal read access long enough to image.
- Chip‑off - remove NAND packages with precision de‑soldering under a microscope to avoid pad damage, then read raw memory and reconstruct ECC, interleaves, XOR, and the FTL offline.
Hardware or firmware encryption, common on modern SSDs, adds another layer: without the right keys, recovery is often impossible.
what recovery looks like in the lab.
HDD techniques
Cleanroom mechanical work: Head stack replacement, preamp fixes, spindle/motor solutions, occasional platter transfers.
Firmware module repair: Correcting translator defects or module corruption so sectors can be read reliably.
Adaptive imaging: Hardware imagers to clone unstable media, mapping bad sectors and retrying selectively to preserve weak areas.
Logical recovery on the clone: File system rebuild, MFT repairs, and file carving performed on the image - not the original drive.
SSD techniques
JTAG interrogation: Spider‑board or pin‑out fixtures connect to controller pads, allowing low‑level commands without removing chips.
Controller/firmware access: Vendor‑specific utilities or terminal access to stabilize the drive and extract a raw image.
Electrical repairs: Replacing shorted components (e.g., power ICs, protection diodes) to regain temporary stability for imaging.
Chip‑off recovery: Removing NAND packages, reading them with specialized programmers, then reconstructing data (ECC, interleaves, XOR, wear‑leveling, FTL).
Dealing with encryption: If the SSD is self‑encrypting, the correct credentials/keys are required; without them, even raw NAND reads are unintelligible.
when DIY works and when it doesn’t.
May be safe (read‑only)
HDD or SSD with purely logical issues (accidental deletion, simple partition loss) and no unusual noises or instability - but avoid writes and clone first if possible.
High risk (seek a pro)
HDD clicking/grinding, won’t spin, or was dropped. Software attempts can worsen platter damage and reduce success rates.
SSD after a deletion/format. Continued use can trigger TRIM/garbage collection that permanently destroys recoverable remnants.
Any drive with encryption or intermittent power/firmware errors.
Any SSD exposed to high heat or showing controller‑level faults.
what to do immediately after data loss.
If it’s an HDD
Power down at once. Don’t keep retrying boots.
Do not open the drive. Dust kills platters; cleanroom conditions are essential.
Avoid repair utilities (e.g., file system “fixers”) on a failing disk - they write to the disk and can overwrite metadata.
Call a recovery lab for a free diagnostic.
If it’s an SSDStop all activity immediately. Every write risks erasing remnants due to TRIM/garbage collection.
Don’t repeatedly power cycle a failing SSD; controller/firmware issues can worsen.
Keep the device cool - avoid direct heat sources that accelerate NAND wear.
Provide any passwords/keys used on the device; encryption affects feasibility and timeline.
Consult a lab that handles controller‑level, JTAG, and chip‑off work.
turnaround expectations and key drivers.
HDDs: Cleanroom parts sourcing and stabilization can take days; once stable, imaging speed depends on media condition.
SSDs: Diagnostics can be quick, but controller‑level, JTAG, or chip‑off reconstruction is meticulous work; encryption can extend timelines or limit outcomes.
Technology trend: As analytical tools and spider‑board adaptors improve, many SSD recoveries that once required chip‑off are now possible via non‑destructive JTAG access - speeding up turnarounds and preserving warranty stickers.
Success rates improve when the device is powered down promptly and handled minimally before imaging.
Relative durability & complexity: SSDs are more shock‑resistant and faster, but they fail at the controller/NAND level; recovery is often more complex - especially when encryption is involved - though better JTAG tooling is simplifying many cases.
Pre‑lab checklist: Supply a concise incident summary (symptoms, error messages or noises, prior DIY attempts) and any passwords or encryption keys; this upfront detail accelerates diagnostics and boosts the odds of full recovery.
need help?
Kotar Data Recovery offers professional, in‑lab recovery for both HDDs and SSDs, and every case begins with a free, no‑obligation diagnostic and estimate. The team delivers cleanroom repairs and imaging for mechanically damaged hard drives, as well as controller‑level, JTAG, and chip‑off flash recovery for complex solid‑state drive failures. Clients benefit from a no‑data/no‑fee guarantee and same‑day courier service.
