I have two external hard drives attached to my desk top computer. One is a WD 10EAVS drive. This one turns on and off automatically when I start or stop my computer. The other is a Maxtor One Touch II. This one has an on off switch and doesn’t tun off when I stop my computer.
I use XP’s “Safely remove hardware” to stop it before I turn it off. Some times I get the message that the drive cannot be stopped at that time. I think the drive is doing a self-check and perhaps rewriting files to other portions of the disk, I’m not sure. Some times I can get this message for 5-10 minutes. However, if I want to stop my computer, the drive seems to be able to shut down with no delay like that. Can anyone explain to me what’s going on? It’s not a real problem, I’d just like to know.
When it says that the drive cannot be stopped right now, that means that some task has a file open somewhere on the drive. You can use something like Process Explorer (which you can download from Microsoft) to see what tasks have what files open.
When you shut the computer down, XP stops all of the tasks. Since the task that had a file open is stopped, the drive is stopped during the normal shutdown procedure without any problems.
If I’m reading the OP correctly, you should always be able to turn the drive off if the computer is shut down. There will never be any activity, even though the drive has power. As engineer_comp_geek has said, if the computer is on and you try to shut down the drive, there may be some process still using it.