Mac Pro 4,1 or 5,1 can’t see internal disk drives in Mavericks or Mountain Lion

Had an interesting issue trying to install/upgrade to Mavericks on an Apple 4,1 Mac Pro Desktop.

It was running Snow Leopard, but if I tried to install Mountain Lion or Mavericks it would give a disk error on reboot into the installer.

I made a USB installer, booted off that, and could see that disk utility couldn’t see any drives inside the installer.

As the equipment was working fine on Snow Leopard, this wasn’t a hardware issue.

I updated the firmware on the machine to the latest version, but still the same issue.
Cleared NV ram, same.
Compared SMC revisions, AHCI firmware revisions against a good machine, everything was the same.
Checked dmesg on the machine during a Mavericks installer boot, and could see that it was having issues with wifi, then with SATA.

I checked the other machine, and saw that it had a different wifi card. Bingo!
I removed the wifi card from the non-working machine, and rebooted back into the installer, and it could suddenly see the drives again.

My conclusion is that the Intel ACH10 drivers, and the Atheros ARB5X86 drivers conflict with each other in 10.8 and above. I tested in the 10.10 beta too to be sure, and had the same issue.

Something apple needs to sort out, I guess..

Interesting issue, it took me a little while to troubleshoot.