Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: off/on switch? Does this external drive have an on/off switch?
Document: This external hard drive is very fast and very quiet. Is an excellent solutions for back ups. The power switch isn't in good and comfortable position. Estetically is nice, but his shape is a limitation in his posibilities of ubication in a desktop.
:-)By the by, the glowing light is pretty neat. It makes drive look alive while it does its thing. And since there is no on/off switch, it reassures me that it is on and functioning.As a note of caution, I have read on other forums the dangers of disconnecting the external drive without performing a safe removal first. I recall several people saying they lost files that way. Yikes!!
Though I've only recently opened my hard drive it's worked flawlessly. Backup is quick and easy, and the device is quiet. The one downside as noted before is the lack of an on/off switch and just a plug-in. However, I wouldn't let that deter you from buying this product, especially when it's on sale.
I do not know if this is a design flaw (no power switch) or just a defective drive. I'm not going to try to find out, as I will simply return it and get another Western Digital. If I plug it into my, already started up, Thinkpad, it will not recognize it--ever. I have to unplug and replug in the power every time I want it to get recognized. What a pain. Returning it.
Fast. Reliable. Just works & works well. No power off switch, so it powers on/off with the PC (the USB connection triggers this).
It does its job well. I've been very careful with it since there are reviews of it overheating. I would have given 5 stars if it had a power switch.
Note that the older My Book model and newer v2.0 (green box) both work basically the same, but Western Digital has done away with the power switch on v2.0.
It is everything as advertised which is good. An added extra is that it powers on only when the USB cable is connected so there is no need to flip another switch. I would not hesitate to buy another when needed.
1) Plug it into a power source that only is on when your computer is on. It doesn't have a power switch, but I have a power strip that is plugged into my backup power UPS and is only on when my whole system is on. That way you don't have to unplug it or lose data, as some users have reported.
Pros: Noiseless, fast, easy to setup, saves desk/table space.Cons: No power off switch, when rebooting PC while connected sometimes the machine hangs (could be an isolated problem).Overall its worth the money!! !
Answer: No, there's no external on/off switch -- however, it does sense when it is plugged into USB, and automatically turns on when plugged in, and goes into standby when the drive is unmounted / unplugged from USB.  It also turns on/off automatically when the computer turns on/off, if left plugged in.  I find that this works out really well.The big LED strip indicates when the drive is on.  It has a separate power supply.