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I am quite surprised to see that Windows Explorer is locking my external hard disk. Is there any reason why explorer.exe is holding on to my external hard disk?

Before I was trying to detach the external hard disk, I was opening a csproj file using Visual Studio 2008. I made sure that I closed down Visual Studio before trying to detach the external hard disk. There was no other active program except Google Chrome, from what I could see, that was running.

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I have found it depends on the drive itself. I have 3 different external hard drives. 2 of them can be disconnected fine using Safe Remove but my Maxtor drive cannot - it always says it is in use. Tools like Unlocker report that nothing is actually open. I have yet to find a solution for this. – Shevek Mar 25 '10 at 10:22
It really is a frustration with Microsoft operating systems; Microsoft seems to have put very little thought into handling external and portable devices. The fact that nothing can tell you what owns a lock is rather appalling but that follows the Microsoft philosophy of never telling you the reason an error has occurred - just try programming in any Microsoft language, be it VBScript, or SQL Server, the error messages have no bearing on the actual cause of the problem. Pity Microsoft employees just aren't interested in technology enough to read forums like these. – PP. Mar 25 '10 at 11:31
  1. Do you have an explorer window open on to the external hard drive?

  2. Have you written a large amount of data to the hard drive recently (within the last few minutes)?

I've noticed that if I do the latter the external hard drive can be locked for a while (I've not measured how long) afterwards. It seems like Windows is "finishing off" the write in the background somehow.

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All I did was opening csproj on the external hard disk, and I make sure I close the VS before trying to detach the external hard drive – Graviton Mar 25 '10 at 9:23
@Ngu - I don't know then. I was just outlining two common cases that get me from time to time. It would be worth adding what you did to the question. – ChrisF Mar 25 '10 at 9:25
i've seen the same kind of thing with the image viewer -- if i explore into a folder, use the builtin viewer on some images, close the viewer and explore to a different folder, that explorer process sometimes keeps a handle open to a directory i had open previously. sometimes opening another image in the viewer is enough to let go of the stale handle. but it's certain that no actual writes were taking place. – quack quixote Mar 25 '10 at 9:32

Things to check:

  1. Is the drive being indexed?

  2. Is the drive set up for write caching?

  3. Is it optimized for "Quick Removal" or "Performance"?

These options should all be found if you right-click/properties on the drive in My Computer

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Use unlocker to check what is holding on to the handles, if it is explorer.exe don't hesitate for a split second to unlock all handles. If it's not explorer, give it a thought and unlock all anyways. This usually helps.

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