Helping people with computers... one answer at a time.
Windows tries to prevent corruption by disallowing removal of USB devices that are "in use". Unfortunately it's not always obvious what "in use" means.
Whenever I plug in a flash drive or my external hard drive (Western Digital My Book), I cannot safely remove when I click on the icon. I keep getting the message that the drive is currently in use -- try again later. But, no matter how many times I try, I keep getting the same message. I end up having to shut down my computer to remove the device.
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Well, windows certainly thinks that some program is attempting to access the USB drive. Since it's not guaranteed to be safe to remove a drive while it's in use, Windows tells you that you can't. The "wait until later" part is all about waiting until that program, whatever it is, is done with the drive.
What program?
Figuring that out is the trick...
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Here's the message we're talking about:
This pops up if you attempt to "safely remove hardware" on an external USB flash or hard drive and Windows thinks that the drive is in-use by some program on your machine.
It turns out that finding out what program that might be isn't particularly obvious, but we can go searching for clues.
Here's the approach I use.
First, go download and run Process Explorer - the free Sysinternals utility from Microsoft.
In Windows 7, either launch Process Explorer with the "/e" option (as in procexp /e - note the space before the /), or once it's running click on the File menu and then Show Details for All Processes. This will cause Process Explorer to re-launch itself with full administrative access. You may get a UAC confirmation. This is required to allow Process Explorer to see "inside of" all processes on the machine.
With Process Explorer running, use its Find menu, Find handle or DLL ... function, and search for \device\harddisk. You should get results similar to this:
You can see that the list includes several entries (yours will almost certainly be different). And it's not at all obvious which hard disk each line represents. However clues are here.
In my case I looked down this list and realized that WS_10001.WMA, listed in the right hand column, is an audio file that I was just listening to. I had failed to close the audio player (mplayerc.exe, listed in the left hand column). I closed the player, and "Safely Remove Hardware" worked just fine.
It's difficult to predict what you'll find that might have something open on your external drive. In my case it was simple, I'd been listening to an audio file that I immediately recognized. The clues you get might not be quite as obvious. In particular, check the list of programs you'll see on the right of your own search results list. See if any of those might have a reason to be accessing the USB drive.
I'm guessing that some of the unexpected offenders you might find in that list include anti-virus programs who've started scanning the drive, anti-spyware tools doing the same, the Windows indexing service (you might need to turn off indexing of the external drive) and other tools that might try to automatically access hard drives that are found on your system.
Article C3246 - December 23, 2007
Leo A. Notenboom has been playing with computers since he
was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed.
After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers
to common computer and technical questions. More about Leo.
I had the same problem with the PID 4/System process. The solution Michael Carter proposed worked for me: I opened the Task Manager, closed explorer.exe in Task Manager and then re-opened explorer.exe in Task Manager. I was then able to remove the external hard drive without a problem. Let me add that this problem occurred repeatedly during the FIRST TIME I used my brand new Windows 7-running laptop. I will shortly contact Microsoft about this.
Posted by: New_Windows_7 at May 25, 2011 3:59 PMHey, it is more simple than all the above comments...just remove the maxtor icon and the autorun.inf and you're done...
Posted by: Merineth Cally at July 25, 2011 10:02 PMComputer Courses Brisbane
I get this error all the time and I thank the author for providing a useful way to find out what is causing the problem. I've found that frequently it's Microsoft's own software that does it; for example, if you've saved an MS Word file to a usb drive, Word will hold onto the drive even if the file is closed until and unless you close out of Word altogether. I find it rather ironic that Microsoft's operating system is incapable of controlling the behaviour of Microsoft's own applications. It might be different if it were a third-party app that was going a bit rogue, but when it's MS going rogue on itself, well....
13-May-2012
Download 'Unlocker': works perfectly for me.
Les Millgate
Posted by: Les Millgate at May 19, 2012 8:07 AMDownload 'Unlocker': works perfectly for me.
Les Millgate
Posted by: Les Millgate at May 19, 2012 8:14 AM