Why SSDs Fail Differently to Hard Drives
A traditional mechanical hard drive (HDD) stores data on spinning magnetic platters. The read/write heads hover nanometres above the platters to read and write data. When an HDD fails, it usually fails mechanically — the motor seizes, the heads crash, or the platters become damaged. You can often hear it happening.
An SSD stores data in NAND flash memory chips with no moving parts. It fails electronically. The failure modes are different:
- Controller failure: The controller chip manages read/write operations, wear levelling, and error correction. If the controller fails, the drive may not be recognised at all, even if the NAND chips containing your data are physically intact.
- NAND chip failure: Individual memory chips can fail. If the data you need was on those chips, it may be unrecoverable. If it was distributed across other chips, partial recovery is often possible.
- Firmware corruption: SSDs run complex firmware. Corrupt firmware can prevent the drive from functioning or hide data that is physically present on the chips.
- Power failure during write: An SSD interrupted mid-write can end up in a state where the filesystem is partially updated and inconsistent.
- Wear-out: NAND flash has a finite write endurance. After enough write cycles, cells degrade and data retention drops. Enterprise SSDs are rated for far higher endurance than consumer drives.
Why SSD Recovery Is Harder Than HDD Recovery
TRIM makes overwritten data unrecoverable
On HDDs, when you delete a file the data isn’t immediately removed — the filesystem marks the space as available, but the actual data remains on the platters until something else overwrites it. This is why standard data recovery software (Recuva, PhotoRec, etc.) can often recover deleted files from HDDs with high success rates.
SSDs use a feature called TRIM, which is supported by all modern operating systems. TRIM tells the SSD to immediately erase blocks that are no longer needed when files are deleted. This improves SSD performance but means deleted files are often immediately and permanently erased at the hardware level.
Practical implication: Standard data recovery software that works well on HDDs often cannot recover recently deleted files from SSDs, because TRIM has already physically erased them.
Data is distributed across chips
SSDs write data across multiple NAND chips simultaneously to improve speed (this is called interleaving). A file is not stored in one place on one chip — it’s spread across multiple chips in fragments. If you were to remove the chips and read them directly (chip-off recovery), you’d have fragments across multiple chips that need to be reassembled in the correct order, with knowledge of the specific interleaving algorithm the controller used.
This is technically possible but requires specialist equipment and expertise. It’s not something standard data recovery software can do.
Encryption is now the default
All Apple Silicon Macs encrypt storage by default using hardware encryption linked to the T2 or M-series security chip. Many modern Windows PCs also encrypt storage by default. On these systems, even if you physically remove the NAND chips and read the raw data, it is encrypted — and the encryption key is tied to the device’s security chip, not the drive itself.
This means that if the logic board fails on an Apple Silicon Mac, data recovery from the SSD chips alone is generally not possible, because the encryption key is gone with the logic board. The entire system needs to be functional (or the key needs to be extractable) for the data to be accessible.
Types of SSD Failure and What’s Recoverable
Logical failure (filesystem corruption, accidental deletion, partition loss)
Recovery outlook: Good to excellent
If the SSD hardware is functioning but the data is inaccessible due to filesystem problems, accidental formatting, partition deletion, or software corruption, standard and professional data recovery tools can often reconstruct the filesystem and recover files.
Note: If TRIM has run since the accidental deletion or formatting, the outlook is worse — especially on consumer SSDs where TRIM runs frequently.
Controller failure (SSD not recognised, not powering up)
Recovery outlook: Moderate — depends on whether data chips are intact
If the controller has failed but the NAND chips are physically intact, a specialist can sometimes replace the controller (if the same model is available) or perform a direct chip-off read. This is complex, expensive, and not always possible — matching controllers is difficult because firmware pairing ties controllers to specific chip configurations.
Firmware corruption
Recovery outlook: Moderate
Firmware tools specific to the SSD manufacturer and model can sometimes repair corrupted firmware and restore access to the drive. This requires specialist tools and knowledge of the specific SSD platform.
Physical NAND damage
Recovery outlook: Poor to partial
If NAND chips are physically damaged (from heat, power surge, or physical impact), data on those specific chips may be permanently lost. If only some chips are damaged and the data you need was not stored on those chips, partial recovery may be possible.
Encrypted drives (Apple Silicon, BitLocker-encrypted Windows)**
Recovery outlook: Depends on security chip status
If the security chip is intact and the drive failure is logical, recovery is often possible with the correct credentials/Apple ID. If the security chip has failed along with the drive, decryption is not currently feasible.
What Works for SSD Recovery
Software recovery (logical failures only)
Tools like R-Studio, GetDataBack, and professional equivalents work for logical SSD failures where the hardware is functioning. They scan the readable portions of the drive and reconstruct filesystem structures.
These tools work less well than on HDDs for the TRIM reason described above, but they’re worth attempting first for accidental deletion or formatting scenarios.
Controller swap
For specific SSD models where a matching controller can be sourced, replacing the failed controller can restore access to the data. This requires matching not just the model number but the exact firmware version and chip configuration. It’s a specialist procedure.
Chip-off recovery
The NAND chips are physically removed from the SSD PCB and read directly with specialist equipment. The raw data is then reassembled with knowledge of the interleaving pattern. This is the most invasive and expensive recovery method, used when other approaches have failed.
This only works for unencrypted drives. On encrypted SSDs, chip-off recovery produces encrypted data that cannot be read without the key.
The Most Important Step: Don’t Make It Worse
As with HDD failure, the biggest risk with a failing SSD is making things worse through uninformed attempts to fix it:
- Don’t run CHKDSK or First Aid on a failing SSD — this can trigger additional TRIM operations
- Don’t attempt to reinstall the operating system — this will overwrite data
- Don’t keep powering the SSD on and off repeatedly — some failure modes are triggered or worsened by power cycles
Power down the machine when you first notice the fault. Contact a professional data recovery service before attempting anything else.
What We Assess and Quote
At our Putney workshop, we assess SSD failures and give you a realistic picture of what’s recoverable before any recovery work begins. We don’t charge for recovery that isn’t successful.
Initial assessment covers: drive recognition, SMART data (where accessible), filesystem status, and encryption status. We’ll tell you what category of failure you’re dealing with and what we expect recovery to yield.
Call 020 7610 0500 or contact us to arrange an assessment.