is it safe to unplug a USB drive while Windows is in sleep/hibernate/off mode?

I have a portable USB flash drive that I use with my netbook. When I'm on the go, it is convenient to be able to simply close the lid and remove my flash drive without first having to use Windows's Safely Remove Hardware routine. The netbook changes to sleep mode (ACPI S3 mode) when I close the lid. Is it possible to do this safely with Windows 7 Home Premium? What about for hibernate (S4) and off modes?

Timothy003

Posted 2010-08-22T03:52:24.587

Reputation: 292

Answers

The "Safely Remove Hardware" routine finishes cached/delayed writes to the drive, so data isn't left in an inconsistent state when the drive is removed. As far as I know, when your netbook changes to sleep mode it also finishes any writing to the flash drive. You can unplug the drive as soon as the netbook is actually in sleep mode (which can take several seconds after you close the lid).

If the netbook is hibernated, it should be safe to unplug the drive. A poorly-written program may throw errors when you resume if it expects the drive to be available.

If the netbook is off, it's always safe to just unplug the drive.

Velociraptors

Posted 2010-08-22T03:52:24.587

Reputation: 1 207

2For the hibernation remember this is basically saving the current state of the computer. So if a program was using that drive you could error it out. – Unfundednut – 2010-08-22T04:04:29.080

1Good point. A well-written program will handle that situation gracefully, but that isn't always the case. – Velociraptors – 2010-08-22T04:13:07.843

1Furthermore, it should be fine if you plug it back in when you return, before turning the computer on. – nhinkle – 2010-08-22T07:07:55.120

1Using your method, I have also found that plugging the drive back in before waking from sleep or resuming from hibernation will appear as if the drive had not been touched, and ReadyBoost doesn't invalidate the cache file, which is a big win. Now, I just have to stop the netbook from waking itself up from sleep before I get the chance to plug the drive back in. Thanks! – Timothy003 – 2010-08-23T04:13:29.457

Tested both suspend and hibernation: suspended or hibernated (my power light glows on and off when done), removed the drive, waited two minutes, plugged the drive back in the same USB port, resumed. I am using Readyboost which makes it obvious on my older computer if the usb drive is functioning rightly and it does. – Todd Partridge – 2018-01-25T19:04:04.943

Hibernate is worse if you're using NTFS. It will cause data loss. see
http://superuser.com/questions/39532/hibernating-and-booting-into-another-os-will-my-filesystems-be-corrupted

– BCoates – 2012-07-24T01:56:39.093

1@BCoates, that question refers to dual-booting Linux and Windows, and the potential corruption is on the NTFS partition with the hibernated Windows install. It doesn't really apply to this question about removing a flash drive while the Windows system is hibernated. – Velociraptors – 2012-07-24T16:47:40.757

It might not generate any problem disconnecting drive while in sleep state.
But you have to make sure that none of the program is being reading any file from that drive(Like playing multimedia file on VLC and putting computer on sleep.)otherwise it may throw a problem on reading the file.

In hibernating the computer will force application to save changes to the file on which they are working so it`s safe.

While turning off computer is the safest way, because

OS will close all running application. (If application is running then it forces to close the app, force close dialog will open.)
If application have modified any file and file is unsaved then force close dialog will be shown. Here you get the scope to save the file, if you don`t then the application will be force closed. The file it was modifying will be on its previous state and will not carry any modification.
Finally it releases all the resources used by the application, and clears the memory buffer.

user144565

Posted 2010-08-22T03:52:24.587

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