Not sure if this is the right place to ask, but here goes ..

I recently bought 2x WD Red Plus 8TB NAS hard drives, and while unboxing them I noticed that they have bumps on their sides, of varying intensities. Please take a look at the pictures below. Are these bumps normal, or are these hard drives potentially damaged/defective ? I bought two of them from the same retailer at the same time, and they both have them. Both have one side with more bumps than the other side. Note that I have not actually used them so far in any way yet.

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Click for larger images

  • Hmm, I never noticed the impurities, but I know that HDD needs to be clean-room clean and stay that way to work, so a simple read/write test will tell you whether the seal has broken. If it isn't sealed, a single piece of dust will scratch up the disk and cause failure pretty quickly.
    – Nelson
    Dec 6 '21 at 1:02

Yes, this is totally normal, and comes from the manufacturing/casting process. Those 'bumps' are impurities/air pockets in the casting process, but since they don’t affect the function of the disk (or the stability of the casing), they are not machined away.


It is probably irrelevant to the functioning of the drive and is pretty common.

The drive chassis will be die cast aluminium, the cheapest way to manufacture with minimal waste, and then processed in a second stage to flatten surfaces that need to mate with other surfaces.

Die casting can result in imperfections in the moulded piece, especially on external surfaces where the cast may be damaged over time while releasing parts or just general wear or tear.

  • 2
    Yes, these are definitely irrelevant to drive functionality. Anything that could potentially affect drive functionality would have been removed in the various stages of cleaning and milling the parts, and QA. Dec 7 '21 at 0:15

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