Z77X-UP5 TH hangs at boot when newly formatted GUID ExFAT HD is plugged in

[quaternio]

As the title says, the Z77X-UP5 TH will not pass the bios load screen while the newly reformatted drive is attached (code on the board says "A2," which is the point at which disk drives are detected). Just before this started, I reformatted what previously had a Windows partition on it to a GUID partition scheme formatted as ExFAT. (I changed some drives around because Windows chose Master Boot Partition by default when I installed Windows on the 3TB drive, rendering 700+GB unusable; I had to change that.)

I don't know if this is a fault of the drive or what. I tried plugging the drive to a different SATA slot, but the result is the same. I also switched to my alternate flash of the motherboard's bios: same result. Both Windows and OS X work fine when I unplug the drive.

Any suggestions?

UPDATE:
I figured out that I could hotplug the drive into the Marvel controller SATA port after I've booted into OS X. Reformatting the drive in question from ExFAT to Mac OS Extended (Journaled) seems to have solved the problem. I wanted to use ExFAT so both OS X and Windows could use the drive, but I can probably make things work with a Windows driver for HFS+ journaled drives.

 

[foreveryoung]

Hello! I got mine to work!!

I have a 3TB hard drive and the same motherboard as you. I used parted magic. I used the disk utility application on it and reformatted the hard drive again to exFAT. I believe OSX corrupts the GUID table when it tries to format the hard drive to exFAT. If you don't want to buy parted magic, try using a free linux distro like ubuntu.

Good luck, please let me know if it works and spread the word.