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Being the good citizen I am, I left-click on the "Safely Remove Hardware" icon in my taskbar, and select my USB drive to dismount.

Then I get the message:

Windows can't stop your Generic volume device because it is in use. Close any programs or windows that might be using the device, and then try again later.

Of course, being the Operating System, it knows exactly what applications are using my device. So why won't it tell me?

Or is there a way that I can find out?

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I have had numerous occasions with Vista where I could never figure it out and it wouldn't "release" the USB until I had re-boot/shutdown. Upgraded to Win7 and have not had that problem since, so I figured, at least on my PC, it was a system driver issue. – BBlake Dec 24 '09 at 19:02
up vote 28 down vote accepted

You can use Sysinternals Process Explorer to find the handle for any files that are open. Just select the Find menu and select Find Handle or DLL. In the dialog that opens enter the drive letter into the search box. The search results should show all of the files that are open from the drive and which process has them open.

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After Killing the offending process, Windows would still not free the USB drive. Go figure.... – Grantly Dec 24 '15 at 13:18

For me (Windows 7).

  1. Hit Windows key
  2. In "search programs and files: type: diskmgmt.msc
  3. In search list find entry and right click - select run as administrator
  4. Enter admin credentials to run "Disk Management" (if required)
  5. Find offending usb drive that won't eject in disk list
  6. Left hand panel, right click select "Eject"
  7. Handles "should" close - you can always double check in sys internals process explorer

Note: "Safely remove hardware and eject media" taskbar icon no longer shows usb drive - just three dots

  1. Physically remove drive
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