I've got a 4x500GB RAID 5 LUN which is served to VISTA as "Tank". From there, I created 2 partitions: "Musicbox" (E:) and "Cinema" (F:). Last night I came home and woke my PC out of sleep, hit a shortcut which was located in the F: partition, and was told that the resource was no longer available. Going into My Computer shows that the drive is no longer there. Windows Disk Manager shows a single healthy partition of the entire 1397GB amount. (no sign of another partition which had been created). The bios RAID tool shows that everything is healthy and served up to the appropriate LUN (all 4 disks in their entirety - 465 x 4 since they were rounded down). I ran Data Recovery tool and it also cannot even see the additional partition which I had created. The RAID set was created over a year ago, and the partition (F:) at the same time, and I had been using it without any problems at all. Now, I wake it up and it is just gone. What the heck happened and is there any way to recover it??? Help! Thanks, PT

Did you try rebooting the computer ?

Sure did. (I've seen "the IT Crowd", so I know my troubleshooting procedures...). I also had to do so to get into the bios RAID tool.

The drive might be reserved for something else, have you tried assigning it a drive letter in Disk Management?