- Networks
- NAS storage
Hard Drive Fault
Western Digital Hard Drive Fault (NAS): drive bad or failed
Risk level
High
Professional inspection is recommended.
Urgency
High
Quick answer
On a Western Digital My Cloud EX2 Ultra NAS, a Red Flashing Front Panel Hard Drive (HDD) LED indicates a Hard drive fault, and Storage > Disk Status in the dashboard identifies whether Drive 1 or Drive 2 is Bad, Failed, or not compatible.
Safety first
Stop and check this first
- Before removing or inserting a drive, power off the unit, disconnect all cables, and ground yourself by touching metal to avoid ESD problems; do not attempt to use the device during the rebuild process.
Safe checks you can perform
- Identify which drive is Bad, Failed, or not compatible in Disk Status
- Run Quick Test or Full Test in Settings > Utilities > System Diagnostics
- Verify replacement drive compatibility and power adapter wattage
Leave these tasks to a qualified professional
- Do not attempt this professional task: Prepare and insert the replacement drive and allow rebuilding without using the device
- Do not attempt this professional task: Power off the unit and remove the faulty hard drive with ESD precautions
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Prepare and insert the replacement drive and allow rebuilding without using the device
What they doUsing a Phillips-head screwdriver, attach the plastic tab and side screw to the replacement drive (or reuse the parts from the faulty WD drive), attach label 1 or 2, slip the drive gently into the slot with the green board facing the middle of the unit, screw the bracket over the tops of the drives, close the door until it locks, reconnect network and power cables, and do not use the device during the rebuild process.
They must show youthe plastic tab sticking up at the back of the unit, the secured bracket, and the new drive detected in Disk Status.
In writingreplacement drive model and serial number, bay 1 or 2 position, and RAID rebuild status.
Power off the unit and remove the faulty hard drive with ESD precautions
What they doThe technician or owner powers off the My Cloud EX2 Ultra, disconnects all cables, places the unit on a clean and stable surface, grounds themselves by touching metal against ESD, presses the top indented button to open the door, removes the holding bracket, and pulls the plastic tab at the back of the faulty drive (Label 1 left, Label 2 right) to guide it out.
They must show youthe Drive 1 (left) or Drive 2 (right) decal matching the Bad or Failed drive from Disk Status.
In writingserial number and bay number of the removed drive and confirmation that all cables were disconnected prior to removal.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Identify which drive is Bad, Failed, or not compatible in Disk Status
- Who:
- you, viewing the Storage section of the My Cloud EX2 Ultra dashboard.
- How:
- on the dashboard navigation panel, click Storage and then click Disk Status; if a drive is Bad, has Failed, or shows not compatible, select Drive 1 or Drive 2 to open the Hard Drive Information dialog box.
- Result that matters:
- confirm the exact drive number (1 on the left or 2 on the right when looking down on the top of the unit), model, and serial number.
- If the status is not compatible after installing a drive:
- replace it with a supported drive from the WD compatibility list (such as WD Red).
- If the drive is listed as Bad or Failed:
- record the serial number for replacement.
- Evidence to keep:
- Hard Drive Information details (Vendor, Model, Serial Number, Capacity, and Firmware Version).
Evidence: My Cloud EX2 Ultra Private Cloud Storage User Manual
Run Quick Test or Full Test in Settings > Utilities > System Diagnostics
- Who:
- you, running drive diagnostics from the Utilities page of the dashboard.
- How:
- click the Settings icon, click Utilities in the left pane, and click Quick Test (takes several minutes) or Full Test (methodically tests each and every sector of the hard drives).
- Result that matters:
- obtain an official pass or fail evaluation of the hard drive's condition.
- If the drive passes the diagnostic test without errors:
- recheck Disk Status in the dashboard.
- If the drive fails the test:
- prepare to power off the enclosure and replace the faulty drive.
- Evidence to keep:
- pass or fail evaluation result from Quick Test or Full Test for Drive 1 or Drive 2.
Evidence: My Cloud EX2 Ultra Private Cloud Storage User Manual
Verify replacement drive compatibility and power adapter wattage
- Who:
- you, preparing the replacement drive before powering off the My Cloud EX2 Ultra.
- How:
- confirm the replacement drive is compatible (WD recommends WD Red hard drive assemblies) and check that a 48W power adapter is used instead of the 36W adapter if two 8TB or larger HDDs are installed.
- Result that matters:
- ensure the replacement drive and AC adapter match Western Digital specifications.
- If the replacement drive is compatible and the adapter rating is sufficient:
- proceed with powered-off drive replacement.
- If two 8TB+ drives are installed on a 36W adapter:
- upgrade to the 48W power adapter.
- Evidence to keep:
- replacement drive model number and power adapter wattage rating (36W vs 48W).
Evidence: My Cloud EX2 Ultra Private Cloud Storage User Manual
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Networks
- Brand
- Western Digital
- Product type
- NAS storage
Known code variants
- Disco Malo o Erróneo
- Drive is Bad or has Failed
- Error en disco duro
- Estado no compatible
- Front Panel Hard Drive LED Red Flashing
- Hard Drive Fault
- HDD LED Red Flashing
- LED del disco duro rojo intermitente
- Status is not compatible
What it means
In the Western Digital My Cloud EX2 Ultra User Manual, the Front Panel Hard Drive (HDD) LEDs table defines a Red Flashing LED as Hard drive fault: a drive is present but has a hard drive fault or failure (and for incompatible drives, the hard drive LEDs blink red rapidly as the unit powers up). In the dashboard under Storage > Disk Status, the affected unit appears as Bad, Failed, or not compatible. This indicator alone never proves the NAS enclosure mainboard is faulty, but it requires identifying Drive 1 or Drive 2 and replacing the faulty hard drive with the unit powered off.
Warnings and stop conditions
- Highsource verified
Before removing or inserting a drive, power off the unit, disconnect all cables, and ground yourself by touching metal to avoid ESD problems; do not attempt to use the device during the rebuild process.
Evidence: My Cloud EX2 Ultra Private Cloud Storage User Manual
Symptoms and causes
Probable causes · in order
- Internal drive fault reported as Bad or Failed in Disk StatusCommon
Drive 1 or Drive 2 has developed a hard drive fault or failure and is listed as Bad or Failed under Storage > Disk Status.
Evidence: My Cloud EX2 Ultra Private Cloud Storage User Manual
- Unsuitable hard drive showing status not compatiblePossible
An incompatible drive was installed; during power-up the Power LED blinks yellow, the HDD LEDs blink red rapidly, and Disk Status shows not compatible.
Evidence: My Cloud EX2 Ultra Private Cloud Storage User Manual
- Two 8TB or larger HDDs installed with the 36W power adapterLess common
When adding two 8TB capacity and above HDDs, the manual states that the 36W power adapter should be replaced with a 48W power adapter.
Evidence: My Cloud EX2 Ultra Private Cloud Storage User Manual
Virtual technician
Does Hard Drive Fault still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
My Cloud EX2 Ultra Private Cloud Storage User Manual
Western Digital · 2026 · official_doc
- 2
Almacenamiento en la nube privada My Cloud EX2 Ultra Manual del usuario
Western Digital · 2026 · official_doc
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