Juggling two external hard drives with Ghost 15

When I bought Ghost, I started with a FreeAgent external hard drive. I soon discovered it didn't have enough capacity to hold a minimum of two backups for each of my main internal drives. So I bought a bigger external (MyPassport) and have been using it for my weekly backups of the C and D drives. I decided I would take the smaller FreeAgent and put a recent backup of the C and D on it, then put it in my safety deposit box as a kind of worst-case emergency backup if I ever lose my C, D and MyPassport. Granted, even if the one in the safety deposit box is only refreshed once every six months, that backup will be missing recent data, but that's life. Here's the problem ...

 

Today I plugged in the FreeAgent and went into Ghost to use the "Manage Backup Destination" tool so I could scrub the old stuff and put on fresh backups destined for the deposit box. When I went into the MBD, it couldn't see the drive. The name of it was listed on a drop-down menu, but the drive and contents were not shown in the table below. I used Windows Explorer to check out the drive, and everythng was visile. I just need to know why Ghost can't see this drive and list its contents? Cleanup, Settings, Delete, Copy and Explore are all grayed out. The only function that shows up is "Move" under the Tasks menu. Yes I looked in the help docs. No luck.