External drives not dismounting/mounting

For the past few days I've been having issues with external drives. One in particular, mounted via a eSata card in my MBP, or via FW800 has the icon gray out when I eject it, but it never dismounts. After disconnecting it it won't remount until I restart the computer. Just tried to mount all my external drives after ejecting the one drive, and none of them are mounting.

This has only been a problem for a few days. No major updates to system software. I did install MS Office 2011.

ANy thoughts?