Raid 5 became unallocated.

Good news! You've been able to recover your data, correct?

There may be several reasons for the issue, but I think it likely that one of the disks in the RAID is bad. If it was the RAID controller itself, then it would have broken the RAID.

A suggested solution is to break the RAID in the BIOS (after backing up the data elsewhere), assign 3 driver letters to each of the disks, then run this to test each of those 3 disks:
SeaTools for DOS and Windows - How to Use

^ That was indeed a good suggestion by Golden. But I shall only add this. I don't think it is necessary to undo the RAID to test the drives individually. Just download the latest version of Seatools for DOS SeaToolsDOS223ALL.ISO (8.45MB) SeaTools for DOS | Seagate burn it to a CD or CD-RW and boot from it. I am almost sure it is going to show your three RAID drives as individual drives. ( As I had mentioned earlier injection of the raid driver is necessary if the DOS has to see it as a single drive.) Simply select the drives and test.

In case the drive tests pass,the other two possible reasons I could think of is a buggy raid driver and a buggy bios. Updating the BIOS and RAID driver to the latest from the motherboard website may resolve the issue. As for as BIOS update is concerned look into what bugs are removed by a particular update by inspecting all BIOS updates release notes and if it mentions raid then the update is imperative.

I am also happy to see the resolved tick mark on this thread.:)

As always I have been lurking and watching this thread.

Glad you folks got things fixed.

I would suggest that Raid is not a replacement for proper backups.
Of course that is just my opinion.

Good work folks.

Happy computing!