Is there a way to "Safely Remove Hardware" from a batch file?

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Summary: Automating the steps required to "safely remove hardware" isn't at all obvious, but it is possible.

Many USB and Firewire devices can be removed from your computer simply by unplugging. Other devices aren't as easy because the operating system might need to complete an operation to shut the device down safely. Windows provides an icon in the taskbar that allows you to "Safely Remove Hardware" but if you want to automate the shutdown as part of a more complex process you need something more.

As an example, I recently purchased a Maxtor external hard drive and before I remove it I'd like to run a batch file that copies a few files around. It would be nice if that batch file could also invoke Windows "Safely Remove Hardware" when it finishes so I can then just unplug the drive.

Now it can.

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Microsoft provides a utility called devcon for free download. It's a "Command Line Uility Alternative to Device Manager". It can actually do many things that I won't get into here, but removing a plug & play device is a simple operation once you know the unique name of the device you want to manipulate.

After you've downloaded devcon, run "devcon status *" in a command window. This will generate a list of all the devices on your system. Look for the line which describes your device. In my case for my external hard drive the (very cryptic) line looks like this:

SBP2\MAXTOR&ONETOUCH&LUN0\0010B9F700AFC279

That full line is a bit much but any substring that remains unique will do. I have another maxtor drive on my system but nothing else that has the phrase "sbp2\maxtor" so I'll use that. The command to safely remove my external drive then becomes:

devcon remove sbp2\maxtor*

The "*" at the end is a wildcard and matches the rest of the string.

Be certain to select the right device. In my case, installing the Maxtor drive actually installed three devices all labeled with "maxtor onetouch" - its firewire interface, its front panel interface, and finally the drive itself. It's the latter that I want to remove. Looking at the details of the "Safely Remove Hardware" dialog will help you select the appropriate entry.

Finally, be careful. Devcon can certainly cause problems if you delete the wrong device by mistake. A reboot or a re-run of the "add new hardware" wizard may restore you, but that's a risk I'd rather avoid.

Related:

• Ask Leo! - Safely Remove Hardware: where did the icon go? How do I safely remove hardware without it?

Article C1883 - January 18, 2004