I have a WD 1TB Elements external hard drive and every time I use the Windows 7 "safely remove" feature, it gives me a dialog telling that a process is using the disk.

Using Sysinternals Process Explorer and the answer on this question (find everything with the drive letter) I get the following result:

What is the $Extend folder and why is it in use? How can I disable it? I cannot remove it using the command line (access denied).

Edit: I've followed the instructions over here and under the registry key

HKLM\SYSTEM\CurrentControlSet\Control\BackupRestore\FilesNotToBackup

I have a

Multi-String Value named IgnoreNTFS with data \$Extend* /s

But this does not make any difference. Also this question is not about a server.

Additionally I can tell that I use a program called mkv2vob to convert video files with a Matroska container into something my PS3 will play. I convert the source files straight from my external HDD, but I would expect if this program does not release the lock on the HDD, surely it cannot be locked if the process isn't even running?