I have a 2.5" Seagate Momentus XT (500GB) in an external housing (http://www.mukii.com.tw/en/products/transimp/tip-230su-bk.html) that connects to a Toshiba Satellite Pro S750 via eSATA.  It uses both an eSATA cable and dual USB cables (the enclosure doesn't power up without the USB connected).  The laptop runs Windows 7 Pro 64 bit.

I discovered smartmontools today when I was trying to troubleshoot what seemed like an extraordinarily warm enclosure.  I used the one that installs with Cycgwin.  Also for the first time today, I could not click on the USB symbol in the notification area and eject the HD.  It said that it was busy.

It's quite a coincidence that this happened for the first time shortly after I used smartctl for the first time.  So I was wondering if anyone else using smartmontools on Windows ran into such coincidences.  I realize that being unable to disconnect USB devices in Windows is not uncommon, but it is for me with this HD on this laptop.  So I was curious as to whether there is a correlation.