how to fix bad sectors on wd external hard drive mac

Even though sectors are quite small, if you were to lose a sector that contained part of a bigger file like a photo, video or word document – you may no longer be able to open those files because a chunk of them is missing. This is a normal part of a hard drive’s operation that’s done to prevent data loss and corruption.Įssentially your hard drive has noticed a problem with a part of the disk and rather than saving your data there with a risk of it getting corrupted, it moves the data to a safe part of the disk and continues on with what it was doing. When your hard drive encounters an error while reading, writing or verifying data it marks the sector as reallocated and then moves the data to a reserved area on the disk (spare sectors that it sets aside). Each sector is quite small, holding just 512B (bytes) of data. Reallocated sectors are parts of your hard drive’s platter that can no longer be trusted to safely store data.

If you’re looking for tools to check your current reallocated sector count you can jump down to ‘How to check for reallocated sectors’ What are reallocated sectors?

But you should seriously read #3 again, that one’s relevant to everyone. Depending on your specific situation, things may not be that bad. If this list made you panic, I apologize.

Or: If your hard drive is still under warranty, send it in for a replacement (but back it up first).

If your data is important to you, you should buy a new hard drive.

There is no fix to lower your reallocated sector count.

Reallocated sectors are bad sectors on your hard drive that have been moved to another part of the disk.

Let’s cut to the chase with a quick 5 point summary: Increases in reallocated sectors are one of the tell tale signs of a drive that’s dying – do not ignore the warnings. If S.M.A.R.T data for your hard drive is showing a number other than 0 next to “ ID 05 Reallocated Sector Count”, I’m going to be up front and let you know that this isn’t a good sign.

How to fix bad sectors on wd external hard drive mac