Then I noticed that my "bay 2" drive partitions were missing from the devices pane in Finder windows.
DU's reduced the partitions (it's my audio drive, and should have fast, normal and backup partitions) to a single, generic entity labelled, "Media", and claims that it's unformatted.
This is not great; the drive's done no work yet other than obviously spinning up whilst the Mac is on and when I filled it with everything audio.

It's a "new" SATA WD 500GB bought in February. System Profiler reports that "there was an error while scanning for Serial-ATA devices", and shows me nothing.
Help please, someone!

PS: I've not rebooted yet as I'm waiting for my internet connection to time out first; will try it in 2 hours.
