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What is a reallocated sectors count?

Educative Answers Team

Reallocated sectors count is the number of sectorsa tiny cluster of storage space usually 512-bytes that are marked as reallocated by the hard drive upon an error. A growing count is generally considered a bad sign and can result in hard drive failure.

Reallocated sector count is part of the S.M.A.R.T hard drive information.

Self-Monitoring, Analysis, and Reporting Technology (S.M.A.R.T) is a monitoring system included in computer hard disk drives.

Reallocated sectors

Reallocated sectors are bad sectors of the hard drive that can no longer be trusted to safely store data. When a hard drive encounters a read/write/verify data error, it marks that sector “reallocated” and transfers the data to another spare sector to prevent the risk of data corruption.

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Should you worry?

A reallocated sector count above zero is not necessarily bad – what’s more important is how that count grows. A continually increasing count is serious and generally an indication of an ​imminent hard drive failure. We recommend you immediately backup your drive and replace it with a new one.

Note: There is no fix that allows you to lower a reallocated sectors count. You are better off getting a new hard drive.

Checking your reallocated sector count

There are several tools available that can display S.M.A.R.T data. For Windows,​ you can use CrystalDiskInfo (free), and for Mac use DriveDx (paid).


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