I no longer needed the use of an external USB HD and wanted to disconnect it so that I can go home. As usual I used the Safely Remove Hardware icon from the system tray. It refused to proceed and notified me that there is a Problem Ejecting USB Mass Storage Device. I know there is a MSKB that explained the supposedly reason for this behavior and offered some resolutions. But I was tired & just wanted to go home. I was not in the mood to follow through with them nor would the customer have allowed me to reboot the PC because of some important work in progress. The first thing I did was carefully recollect what application I have used with the drive. It was Windows Explorer. I ran Explorer again and pointed it to open a so and so file on the hard drive then closed it. Then I tried the Safely Remove Hardware icon again. Lo & Behold the USB HD was free to be dismount! I hope this will in some way help many of you facing the same situation. i_Xp/VistaUser

Typo I ran Explorer again and pointed it to open a so and so file on the hard drive.. should read I ran Explorer again and pointed it to open a so and so file on the computer hard drive ... i_Xp/VistaUser

I have had a similiar experience with my USB 320GB drive. Windows Explorer had the drive tied up and I couldn't safely remove. Kept getting a message the drive is busy, try later. I had to shut down Windows to get the drive offline. Have to remember your tip, should that happen again.

I just realized that Windows sometimes commit to memory where every applications were last used until you reboot the PC. By running again whatever you used with the USB device and point it to someplace else other than the USB itself, and then close it, Windows will no longer remember it tied to USB. i_Xp/VistaUser

I wonder if programs such as RAM defrag, RAM Def XT, could "release" the locked memeory of programs that have been closed.