The “Drive Not Ready (DNR)” error reported by computer and NAS systems is an interesting one. For hard disk drives (HDD), a DNR error means that the drive is unusable or has failed. A DNR indicates that the SATA or NVMe interface is working but that the drive is not ready due to an internal drive error.
Here are some possible causes for a DNR:
Mechanical Failure
Issues like a faulty spindle motor or other mechanical components prevent the drive from spinning or accessing data properly.
Electrical Failure
Electrical problems, such as malfunctioning IC chips, damaged circuits, or power supply instability can result in a DNR error.
Servo System Failure (HDD)
If the servo systems fail, often due to electrical issues, the drive cannot accurately follow or retrieve data from the media.
Data Corruption
When the drive is unable to access the data stored on the surface of the media, a DNR error can occur.
A DNR error implies that the drive is critically damaged, and data recovery is typically impossible. The drive needs to be removed from the system and replaced with a working drive.
In some cases, the drive might return to working condition if the DNR was due to unstable power supply or voltage. Even if the drive works again, users should immediately back up the data and replace the drive to prevent further failure.
The DNR error itself does not necessarily mean the drive is broken, but if it is caused by hardware problems or file system corruption, it may signal declining drive health. Ignoring the error could lead to data loss via a damaged drive, so it’s important to check other symptoms as soon as you see a DNR error.
ULINK DA Drive Analyzer makes monitoring drive symptoms much simpler. It can send you alerts and notifications for drive health issues like Device Not Ready (DNR) Errors. Using Explainable AI, it provides you with a detailed analysis of the possible underlying causes of drive deterioration and can help you make an informed decision about the future course of action.
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Photo Credit: Klimenko Aleksandr