A 4TB Toshiba External Hard Drive Cleanroom Recovery Case
We received an enquiry for data recovery involving a 4TB Toshiba external desktop hard drive which had Western Digital 4TB 9WD Blue) Desktop drive installed. The client shared a video (attached below) clearly showing that folders were visible and accessible, but whenever data copying was attempted, the system became non-responsive.
At first glance, this behavior commonly points toward bad sector issues, which is why proper diagnosis is critical before any recovery attempt.
Initial Assessment and Client Input
During the enquiry stage, we asked the client standard diagnostic questions, including:
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Whether the drive had been dropped
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Whether it had experienced electrical shock or power surge
The client confirmed no physical drop or shock had occurred. Based on the symptoms and the information provided, we initially quoted a bad sector data recovery price.
The client then brought the drive to our service center for in-depth diagnosis.
Diagnostic Findings Using Professional Recovery Equipment
Once connected to our professional data recovery equipment, the issue became immediately clear.
Head-by-Head Read Analysis
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Heads 0, 1, and 2: Reading normally
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Head 3: Reading at only 300–400 bytes per second
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Continuous production of bad sectors during reading
At this speed, reading a full 4TB drive would require approximately 4,286 days — nearly 12 years to complete imaging.
We will attach the actual image showing the real-time reading speed recorded during diagnosis.
At this point, it was evident that this was not a standard bad sector case.
Cleanroom Inspection: Identifying the Real Cause
We proceeded with a cleanroom inspection and opened the drive in front of the customer for full transparency.
Cleanroom Findings
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The top platter surface, corresponding to Head 3, had visible scratches
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This confirmed that Head 3 had collided with the platter surface
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The collision caused head degradation, explaining the extremely slow read speed
This physical damage clearly explained:
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Why the drive froze during copying
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Why bad sectors appeared progressively
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Why software-based or prolonged reading attempts would fail
We will attach photos of:
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The scratched platter surface
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The 4TB donor head stack
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Donor and patient drives on the cleanroom desk
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Before and after head replacement
Revised Recovery Strategy and Client Approval
After explaining all findings to the client and demonstrating the issues live, we revised the recovery approach.
Updated Plan
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Head stack replacement using a compatible 4TB donor drive
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Controlled cleanroom intervention
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Stabilized imaging after head replacement
A revised quote was provided for head replacement data recovery, reflecting the actual complexity and risk involved.
The client approved the revised recovery plan.
Why Reading at Slow Speed Is Not a Solution
Many assume that “slow reading” will eventually recover data. This case proves otherwise.
At 300–400 bytes per second, the drive:
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Would take over a decade to image
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Would continue degrading platter surfaces
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Would risk complete servo destruction
Professional recovery focuses on eliminating the root cause, not waiting indefinitely.
Final Outcome
After successful head replacement:
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The drive stabilized
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Data was imaged safely
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Recovery was completed successfully
This case highlights how what looks like a logical problem can actually be a critical physical failure.
Key Takeaway for Drive Owners
If your external hard drive:
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Shows folders but freezes during copying
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Produces increasing bad sectors
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Becomes extremely slow during read operations
The issue may not be bad sectors alone — it could be failing read/write heads.
Early professional diagnosis can prevent:
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Years of ineffective attempts
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Escalation to permanent data loss
Why Professional Cleanroom Diagnosis Matters
At GeeksAtHelp, we perform transparent, head-level diagnostics and cleanroom inspections to identify the true cause of failure. This ensures the recovery strategy is accurate, efficient, and safe for your data.