Remove USB device from command line
Solution 1:
RemoveDrive has served me well in the past
Solution 2:
Besides Uwe Sieber's RemoveDrive mentioned in the other answer, there are a whole bunch of utilities that can accomplish this. A small list follows:
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USB Disk Ejector is primarily a GUI-based utility but can be used equally well from the command-line to eject the drive that the program is running from, or any drive by specifying the drive letter / (partial) drive name / mountpoint etc. Free and open source.
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USB Safely Remove is not free but it's a disk removal utility on steroids, with lots of advanced features, including of course command-line support. Zentimo is its bigger brother, with even more features.
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Microsoft's own DevCon is the command-line version of Device Manager. Besides the original Win2K/XP-era version available from the KB page, there are newer releases (both 32 and 64-bit) available from various MS sources as mentioned in this Where to find DevCon.exe article. DevCon.exe for Windows 7 (and probably Windows 8 as well) can be found buried in the appropriate Windows Driver Kit (WDK), as mentioned in this thread (which also contains download links to the extracted executable).
devcon status *
ordevcon hwids *
ordevcon findall =usb
(for a more compact listing) should tell you the hardware ID of the device. For example:USB\VID_0781&PID_7113\0001162825
Name: USB Mass Storage Device
Driver is running.You can then try removing the device with
devcon remove "USB\VID_0781&PID_7113"
(wildcards like * are allowed, but be careful or you might end up removing something else entirely!)
Someone asked "Is there a DOS prompt (cmd.exe from Win7) command to eject a thumb drive?" which was unfortunately closed as a duplicate of this thread. However, the question was about ejecting USB drives while in the Windows Recovery Console / System Recovery Command Prompt, so it is unlikely any of the utilities above will help. In such a situation, the following method using Diskpart should work:
Type
diskpart
and wait for the diskpart prompt (DISKPART>
)Type
list volume
Note the volume number of the USB drive carefully (use listed properties such as drive letter, label, type and size for help)
-
Type
select volume <number>
, where<number>
is the volume number noted above Type
remove all dismount
Type
exit
to quit Diskpart
Now you should be able to safely remove your USB drive without fear of data loss.