Turning off the device is essentially the same as unplugging it, so the short answer is no, it’s not a safe alternative.
Sometimes, a USB device appears to be in use for no apparent reason and cannot be stopped. I’ll walk through some of the approaches you can take to removing the device while minimizing the risk of data loss.
Spoiler: pulling the plug or turning off the power aren’t on the list.
Here are a few things I check when I encounter this error (which is often).
Sometimes the error message is spot-on: I’ll be running a program of some sort that happens to be in the process of accessing the external drive. Perhaps most embarrassing is discovering that the backup program I’ve explicitly instructed to access the drive to create a backup is accessing the drive.
Check for any programs you are running that might, in fact, be accessing that external drive.
File Explorer or Command Prompt
Next I check for any copies of Windows File Explorer or Windows Command Prompt that are open, displaying the contents of the drive, or have that drive set as the “current” drive.
This is by far the most common cause on my machine. I was doing something that involved examining or otherwise operating on the drive, and I failed to actually stop using it.
Simply closing whichever I find, or having it display something else that isn’t the removable device, instantly resolves the issue.
Use Process Explorer
Next, I’ll run Process Explorer, as outlined in Why Do I Get “device … cannot be stopped right now” Trying to Safely Remove My USB Drive?, and use it to see what application might have a file or “handle” open to something on the removable device.
Once I identify the application, I take action appropriate to that program — doing whatever makes sense in that application to stop it from using the external drive.
If it’s a system process, I might opt for the next option.
If I can, I’ll wait awhile.
Seriously: sometimes the process using the external drive will just disappear on its own. Common processes that fall into this category include the content indexing service, as well as Windows Defender or other anti-malware tools that scan the drive.
If you’ve ruled out everything else above, and can wait a few minutes, do so and try again. It works surprisingly often.
Shut ‘er down
Finally, I’ll shut down the machine.
This is the ultimate solution. Once the machine has been shut down, by definition it’s safe to remove anything you want.
I’ll be honest.
Sometimes, I don’t follow my own advice. And because it’s so common for others to do the same, I want to explain the risks and what I do to minimize them.
If none of the steps (short of rebooting) have worked, I’ll wait a while, paying careful attention to disk activity. If the device has truly been idle for “awhile” — I’ll disconnect it anyway.
I need to be clear: if you follow my example, you may lose all the data on the device. Heck, in theory you may lose the USB device itself, though I’ve never heard of that happening.
It’s a risk I run because I’m impatient and don’t want to wait for a reboot. And usually it works.
But I’m also very well backed up. I would never take that inappropriate shortcut if the USB device held the only copy of something.
So, weighing all the risks, I sometimes break the rules. I include it here because there are times you are honestly in a hurry, or a reboot just isn’t in the cards for some reason.
I don’t recommend you do the same, though I realize that sometimes you will.