I have a 1TB external hard drive. Whenever I try to safely remove it, it says that the device is still in use.
I looked through all my processes and I can't find anything using the device. It's annoying since I always have to unplug the device, which I know is not good.
I recently installed a clean version of Windows 7 and the problem still occurs. What could be the cause?

task manager->performance->resource monitor->disk. Indisk activity, sort byfile. See if any file from the drive is being accessed – Akash May 6 '12 at 18:02