I noticed something weird today. I left my USB drive (SANDISK) on my desktop computer. When I unplug the USB after a few days, I noticed that the USB drive is warm. (I didn't turn the computer on at all)

I thought that it was just my feeling, so I tried it several times by plugging it in and unplug it out after a few minutes, and it really feels warm. I also tried with several different USBs. 2 other USB drives (another SANDISK and other brand), they also get warm. However my other USB drive (Silicon Power) doesn't get warm.

I have a concern whether my motherboard or USB drive has been compromised or have some malware on it. The motherboard I'm using is Biostar

Is it normal? Or am I just being too paranoid?

  • Many computers continue to supply power to USB ports even while turned off, particularly desktop computers. Laptops likely do this less.
    – Mokubai
    Jan 13, 2021 at 10:51
  • so this is normal?
    – bbnn
    Jan 13, 2021 at 10:53
  • 1
    At least kind of normal. It depends on the motherboard, software and power saving settings.
    – Mokubai
    Jan 13, 2021 at 11:10

1 Answer 1


External USB enclosures tend to just spin up HDs as soon as the power is switched on. It saves them having to properly negotiate with an unknown controller & OS as to when to spin up/down.

The end result is that there's always sufficient activity to keep the casing slightly warm.

SSDs will suffer from this less, as there's no mechanical component, but are still likely to have some kind of persistent state for when they're connected to a computer.

  • so my USB drive gets warm even when the computer is turned off is normal?
    – bbnn
    Jan 13, 2021 at 10:51
  • If it's getting power, yes.
    – Tetsujin
    Jan 13, 2021 at 14:49

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