External HDD won't eject?

I recently got a 2TB G-Drive from the Apple Store and it works great. I've had no problems with it, except this—it won't eject. I have tried ejecting via Disk Utility, right-clicking the HDD icon and clicking eject, and dragging the HDD icon to the trash. Whenever I try to do any of those three methods, I get this message:



Any thoughts? I'm running no programs except Chrome right now. My only concern is that if I hit Force Eject I may corrupt the drive. I don't need to eject the drive right this minute, but when I need to take it somewhere I will need to eject it before I can turn it off (the drive has an on/off switch).

 

Ha, that's funny, a reboot fixed it. Thanks.