# Is it safe to shut down/restart computer with portable HD on?

**URL:** <https://boards.straightdope.com/t/is-it-safe-to-shut-down-restart-computer-with-portable-hd-on/649304>\
**Category:** Factual Questions\
**Created:** [February 4, 2013, 2:23pm UTC](https://boards.straightdope.com/t/is-it-safe-to-shut-down-restart-computer-with-portable-hd-on/649304 "2013-02-04T14:23:33Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![cultivar07](https://avatars.discourse-cdn.com/v4/letter/c/71c47a/32.png) [@cultivar07](https://boards.straightdope.com/u/cultivar07)\
**Post date:** [February 4, 2013, 2:23pm UTC](https://boards.straightdope.com/t/is-it-safe-to-shut-down-restart-computer-with-portable-hd-on/649304/1 "2013-02-04T14:23:33Z")

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Is it safe to shut down/restart computer, while your PORTABLE hard drive (the kind that is powered via USB only) is connected? Should you disonnect the portable HD first by “safely removing hardware”?

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**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\
**Post date:** [February 4, 2013, 2:28pm UTC](https://boards.straightdope.com/t/is-it-safe-to-shut-down-restart-computer-with-portable-hd-on/649304/2 "2013-02-04T14:28:22Z")

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Yes it’s safe if you use the shutdown process, not just cut the power.

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**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\
**Post date:** [February 4, 2013, 2:53pm UTC](https://boards.straightdope.com/t/is-it-safe-to-shut-down-restart-computer-with-portable-hd-on/649304/3 "2013-02-04T14:53:47Z")

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Yes, nothing wrong with it.

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**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\
**Post date:** [February 4, 2013, 3:26pm UTC](https://boards.straightdope.com/t/is-it-safe-to-shut-down-restart-computer-with-portable-hd-on/649304/4 "2013-02-04T15:26:55Z")

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Apparently, it’s not safe to unplug the drive while the computer is sleeping, though.

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**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\
**Post date:** [February 4, 2013, 4:11pm UTC](https://boards.straightdope.com/t/is-it-safe-to-shut-down-restart-computer-with-portable-hd-on/649304/5 "2013-02-04T16:11:20Z")

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> [@AaronX](#):
>
> Apparently, it’s not safe to unplug the drive while the computer is sleeping, though.

potentially, if the OS has not finished flushing data from cache to the disk before entering standby. At least as far as Windows goes, if a drive or volume is “removable” then it should disable write caching automatically for that drive.

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**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\
**Post date:** [February 4, 2013, 4:24pm UTC](https://boards.straightdope.com/t/is-it-safe-to-shut-down-restart-computer-with-portable-hd-on/649304/6 "2013-02-04T16:24:16Z")

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I’ve seen cases where the computer doesn’t boot properly if there’s a USB drive connected; I guess it’s because the computer is trying to boot off the USB drive and failing. It shouldn’t cause any risk to the data on the drive though.

Shutting down is obviously safe, as the OS dismounts all drives as it’s shutting down.